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The Aptima Combo 2® assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal disease using the Panther® system as specified.
On the Panther system, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, PreservCyt® Solution liquid Pap specimens, vaginal, throat, rectal, and male urethral swab specimens; patient collected vaginal swab specimens , and female and male urine specimens.
¹Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The Aptima Multitest Swab Specimen Collection Kit has not been evaluated for home use.

The Aptima Combo 2® assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the Tigris® DTS® Automated Analyzer. The assay may be used to test the following specimens from symptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; and female and male urine specimens. The assay may be used to test the following specimens from asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; patient-collected vaginal swab specimens'; and female and male urine specimens. The assay is also intended for use with the testing of gynecological specimens, from both symptomatic and asymptomatic patients, collected in the PreservCyt® Solution.
1 Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The Aptima Multitest Swab Specimen Collection Kit is not for home use.

The Aptima Trichomonas vaginalis Assay is an in vitro qualitative nucleic acid amplification test (NAAT) for the detection of ribosomal RNA (rRNA) from Trichomonas vaginalis to aid in the diagnosis of trichomoniasis using the Panther System. The assay may be used to test the following specimens from symptomatic or asymptomatic women: clinician-collected endocervical swabs, clinician-collected vaginal swabs, and specimens collected in PreservCyt Solution.

The Aptima Trichomonas vaginalis Assay is an in vitro qualitative nucleic acid amplification test (NAAT) for the detection of ribosomal RNA (rRNA) from Trichomonas vaginalis to aid in the diagnosis of trichomoniasis using the Tigris® DTS® System. The assay may be used to test the following specimens from symptomatic or asymptomatic women: clinician-collected endocervical swabs, clinician-collected vaginal swabs, female urine specimens, and specimens collected in PreservCyt Solution.

The Aptima Combo 2 Assay (AC2) combines the technologies of target capture, TMA, and DKA. Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the Aptima Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deoxyadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the polydeoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification.
Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Aptima Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded nucleic acid chemiluminescent probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The updated version of the Aptima Combo 2 assay incorporates a second CT probe, complementary to a unique region of the existing CT amplicon. This tandem probe provides detection coverage for the variant strains of C. trachomatis that emerged in 2019. The labeled probes combine with amplicon to form stable hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled hybrids is measured as photon signals in a luminometer and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

The Aptima Trichomonas vaginalis Assay (ATV) involves the technologies of target capture, transcription-mediated amplification (TMA), and hybridization protection assay (HPA). Specimens are collected and transferred into their respective specimen transport tubes. The transport solution in these tubes releases the rRNA target and protects it from degradation during storage. When the Aptima Trichomonas vaginalis Assay is performed in the laboratory, the target rRNA is isolated from the specimens by the use of a specific capture oligomer and magnetic microparticles in a method called target capture. The capture oligomer contains a sequence complementary to a specific region of the target molecule as well as a string of deoxyadenosine residues. During the hybridization step, the sequence-specific region of the capture oligomer binds to a specific region of the target molecule. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecule bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification inhibitors. After the target capture steps are completed, the specimens are ready for amplification.
Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Hologic TMA reaction amplifies a specific region of the small ribosomal subunit from T. vaginalis via DNA and RNA intermediates and generates RNA amplicon molecules. Detection of the rRNA amplification product sequences is achieved using nucleic acid hybridization (HPA). A single stranded chemiluminescent DNA probe, which is complementary to a region of the target amplicon, is labeled with an acridinium ester molecule. The labeled DNA probe combines with amplicon to form stable RNA:DNA hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer and are reported as Relative Light Units (RLU).

Acceptance Criteria and Device Performance for Aptima Combo 2 Assay and Aptima Trichomonas Vaginalis Assay (RMR Probe Reagent Update)

This document describes the acceptance criteria and the studies that demonstrate the device meets those criteria, specifically concerning the manufacturing change to the Ready-Made Reagents (RMR) Probe Reagent for the Aptima Combo 2 Assay (AC2) and Aptima Trichomonas Vaginalis Assay (ATV). The core of this submission is to prove that the removal of the lyophilization step for the RMR Probe Reagent does not negatively impact assay performance compared to the previously cleared predicate devices.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly defined by demonstrating comparability to the predicate devices. The key performance metrics evaluated are Intended Use (overall agreement with expected positivity) and Limit of Detection (LoD). For clinical performance, the acceptance criteria are 100% agreement between the predicate and the modified RMR assay. For LoD, the acceptance criterion is that the RMR assay's LoD is within ½ log of the predicate assay's LoD.

2. Sample Size for the Test Set and Data Provenance

Intended Use Study:

• Aptima Combo 2 Assay (Panther): Negative and positive panels (exact number of panels or individual samples not specified, but stated to include CT positive, FI-nvCT positive, and CT/GC dual positive panels).
• Aptima Combo 2 Assay (Tigris): Negative and positive panels (exact number of panels or individual samples not specified, but stated to include CT positive, FI-nvCT positive, and CT/GC dual positive panels).
• Aptima Trichomonas Vaginalis Assay (Panther): Negative, TV positive, and TV low positive panels (exact number of panels or individual samples not specified).
• Aptima Trichomonas Vaginalis Assay (Tigris): Negative, TV positive, and TV low positive panels (exact number of panels or individual samples not specified).
• Data Provenance: Not explicitly stated, but these appear to be contrived panels (controlled positive and negative samples) rather than directly clinical specimens for this specific study.

Limit of Detection (LoD) Study:

• Aptima Combo 2 Assay (Panther & Tigris): Stocks of CT and GC organisms, and FI-nvCT in vitro transcript. These were run in negative clinical liquid pap specimens collected in PreservCyt solution (ThinPrep).
• Aptima Trichomonas Vaginalis Assay (Panther & Tigris): Stocks of TV organisms in negative clinical liquid pap specimens collected in PreservCyt solution (ThinPrep).
• Data Provenance: The base matrix used for spiking was "negative clinical liquid pap specimens," suggesting these are retrospective clinical samples from an unspecified origin, used in a prospective manner for LoD determination.

Clinical Performance Study:

• Aptima Combo 2 Assay (Panther): 219 remnant clinical swab specimens.
• Aptima Combo 2 Assay (Tigris): 200 remnant clinical swab specimens.
• Data Provenance: "remnant clinical swab specimens". This indicates these are retrospective samples collected from prior clinical testing, with the country of origin not specified.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The ground truth for these studies is established by the performance of the predicate AC2 assay or ATV assay, which was previously cleared by the FDA. The document does not describe the involvement of additional human experts for the ground truth of these specific comparability studies, as the goal is to show the new RMR Probe Reagent performs equivalently to the already established predicate. The reliability of the predicate assays themselves would have been established through prior studies reviewed by the FDA, presumably involving expert consensus or validated methods.

4. Adjudication Method for the Test Set

Adjudication methods were not applicable in these studies. The assessment compares the performance of the modified AC2/ATV RMR assays directly against the predicate AC2/ATV assays. The predicate assay's result is used as the reference/ground truth for comparison. There is no mention of a separate expert adjudication process for discordant results between the predicate and the modified device in these comparability studies. In the LoD studies, the ground truth for spiked samples is defined by the known concentration of the spiked organisms/transcripts.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was done. This study concerns an in vitro diagnostic (IVD) device (nucleic acid amplification test) for direct detection of pathogens, not an AI-assisted diagnostic tool for human readers. Therefore, there is no human-in-the-loop performance to evaluate, and thus no effect size for human reader improvement with AI assistance.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance)

The studies presented are effectively standalone performance evaluations of the modified IVD assays. The assays are fully automated on the Panther and Tigris systems, and the results are interpreted based on predefined cut-offs (Relative Light Units and kinetic curve type). There is no human intervention in the result determination process once the assay is run. The comparison is between two versions of an automated assay.

7. Type of Ground Truth Used

• Intended Use Study: The "expected positivity results" indicate that calibrated positive and negative control panels (contrived ground truth) were used. These panels simulate clinical conditions but are created in a controlled laboratory setting.
• Limit of Detection (LoD) Study: The ground truth for LoD was spiked negative clinical specimens with known concentrations of target organisms/transcripts. This is a form of contrived ground truth based on quantitative standards.
• Clinical Performance Study: The ground truth for the clinical comparability study was the result of the predicate AC2 assay. This means the predicate assay's output was considered the reference standard, rather than an independent expert consensus or pathology review of the remnant specimens themselves for this specific comparability study. The performance of the predicate itself would have been validated against clinical outcomes or a gold standard during its initial clearance.

8. Sample Size for the Training Set

No training set is explicitly mentioned or relevant for this submission. This submission describes a manufacturing change to a reagent component of already cleared IVD assays. The assays are based on established molecular biology principles and do not involve machine learning algorithms that require a training set to "learn" patterns or make predictions. The "development activities" mentioned relate to design control and verification testing, not algorithmic training.

9. How the Ground Truth for the Training Set Was Established

As there is no training set for an algorithm, this question is not applicable.

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The Aptima Combo 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal disease using the Panther System as specified. On the Panther System, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, PreservCyt® Solution liquid Pap specimens, vaginal, throat, rectal, and male urethral swab specimens; patient-collected vaginal swab specimens1, and female and male urine specimens.

The Aptima Combo 20 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the Tigris® DTS® Automated Analyzer or semi-automated instrumentation as specified. The assay may be used to test the following specimens from symptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; and female and male urine specimens. The assay may be used to test the following specimens from asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; patient-collected vaginal swab specimens'; and female and male urine specimens. The assay is also intended for use with the testing of gynecological specimens, from both symptomatic and asymptomatic patients, collected in the PreservCyt® Solution.

The Aptima Combo 2 Assay combines the technologies of target capture, TMA, and DKA. Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the Aptima Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deoxyadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification.

Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Aptima Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded nucleic acid chemiluminescent probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The updated version of the Aptima Combo 2 assay incorporates a second CT probe, complementary to a unique region of the existing CT amplicon. This tandem probe provides detection coverage for the variant strains of C. trachomatis that emerged in 2019. The labeled probes combine with amplicon to form stable hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled hybrids is measured as photon signals in a luminometer, and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection reaction for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

The provided text describes a 510(k) premarket notification for a modified diagnostic device, the Aptima Combo 2 Assay, used for detecting Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC). The modification involves a change in the Probe reagent to improve detection of emerging CT variants.

Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The FDA 510(k) submission process for in vitro diagnostic devices focuses on demonstrating substantial equivalence to a legally marketed predicate device. For modifications to an existing cleared device, the key acceptance criteria revolve around showing that the changes do not negatively impact the assay's performance, safety, and effectiveness, and specifically address the reason for the modification (improved CT variant detection).

While explicit enumerated "acceptance criteria" with numerical thresholds are not presented in a table format as might be seen for a new device, the document implies the following performance criteria were met:

2. Sample Sizes Used for the Test Set and Data Provenance

• Limit of Detection (LoD) Study:

  • Sample Size: 30 replicates of each dilution were tested for each specimen type (urine, ThinPrep, simulated swab matrix). This was done with 3 reagent lots on both Panther and Tigris systems.
  • Total replicates: 30 (replicates/dilution) * 3 (specimen types) * 3 (lots) * 2 (systems) = 540 replicates per target organism (CT/GC).
  • Data Provenance: In vitro transcripts diluted in negative urine specimens, negative ThinPrep specimens, and simulated swab matrix specimens. This is laboratory-derived analytical data, not directly stated to be from a particular country. It is essentially prospective in nature for validating the new formulation.

• Clinical Comparability Study:

  • Sample Size: Not explicitly stated as a total count, but implied by the comparison tables below Table 4 and Table 5.
    • CT: 49 CT positive, 273 CT negative, 3 discordant (updated positive, current negative). Total: 325 remnant samples.
    • GC: 47 GC positive, 275 GC negative, 1 discordant (updated positive, current negative). Total: 323 remnant samples.
  • Data Provenance: Remnant swab specimens collected from patients undergoing CT and/or GC screening. The origin country is not specified, but it's retrospective use of existing clinical samples.

• CT/GC Clinical Panel Agreement Study:

  • Sample Size: 20 prepared CT/GC clinical panels. Each panel was tested in triplicate, in two runs per day, on three Panther systems, by two operators, using three lots of reagents over seven days.
  • Total tests: 20 (panels) * 3 (replicates) * 2 (runs/day) * 3 (systems) * 2 (operators) * 3 (lots) * 7 (days) = This calculation seems off and yields a very large number. More simply, if each panel was tested in triplicate across the stated conditions, the total number of data points specifically for these panels would be substantial. The document states "Each of the 20 panels were tested in triplicate...over seven days", implying multiple runs under varying conditions, leading to hundreds of data points (e.g., 20 panels * 3 replicates * 2 runs * 3 systems * 3 lots * 2 operators * 7 days if all combinations were run, which is impractical; more likely "across" these variables). Let's interpret "in triplicate...over seven days" as at least 3 runs per panel across variable conditions for a total of 60 tests (20 panels * 3 replicates) per condition (e.g., per system/lot/operator combination). The key is "The results show 100%...total CT and GC agreement to the expected panel result for the updated AC2 assay."
  • Data Provenance: Prepared clinical panels containing known concentrations of wild type CT, FI-nvCT, and GC in urine specimens. This is an expertly constructed analytical study, effectively prospective in its execution for validation.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications

The document does not mention the use of human experts (e.g., radiologists) for establishing ground truth for a test set. This is a molecular diagnostic assay, not an imaging device. Ground truth for these studies is typically established by:

• Analytical studies: Known concentrations of purified nucleic acids (e.g., in vitro transcripts) or spiked microorganisms.
• Clinical comparability: Agreement with a legally marketed predicate device (the "current" AC2 assay) on remnant clinical samples. The predicate device itself was cleared based on its own performance studies.
• Clinical panels: Known concentrations of target organisms in simulated or real matrices.

Therefore, the concept of "experts" in the context of ground truth establishment for this specific device would relate to the scientific team involved in designing the analytical panels and interpreting the molecular results, rather than clinical experts adjudicating cases.

4. Adjudication Method for the Test Set

Not applicable in the typical sense for this type of device. There's no "adjudication" of images or clinical cases by multiple readers. The output of the device is a qualitative "positive" or "negative" result based on Relative Light Units (RLU) and kinetic curve type. Equivalence is determined by statistical agreement (percent agreement) between the test device and the predicate or expected panel results.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No. An MRMC study is relevant for imaging devices where human readers interpret medical images, often with and without AI assistance, to assess diagnostic performance. This document concerns a molecular diagnostic assay where a laboratory instrument provides a qualitative result. There is no human "reading" of the assay outcome in the same way an image is read.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, implicitly. The performance data presented (LoD, clinical comparability, clinical panel agreement, cross-reactivity) are all "standalone" in the sense that they demonstrate the analytical and clinical performance of the assay system itself (reagent + instrument) without any direct human interpretation of raw data (beyond standard laboratory procedures for operating the instrument and interpreting its final qualitative output, which is not "in-the-loop" AI assistance). The device is intended to provide a diagnostic result directly.

7. The Type of Ground Truth Used

• Analytical Studies (LoD, Cross-Reactivity, Microbial Interference): "Spiked" or "known concentration" ground truth. For example, FI-nvCT in vitro transcripts at varying known concentrations, or panels of known microorganisms.
• Clinical Comparability: The results from the predicate device (current AC2 assay) on remnant clinical samples served as the de-facto ground truth for evaluating equivalence. While not "absolute" ground truth (like pathology), it's the standard for substantial equivalence in device modifications.
• Clinical Panel Agreement: Expected panel result based on known concentrations of spiked organisms. This is a form of engineered, highly controlled ground truth.

8. The Sample Size for the Training Set

The document does not directly disclose the sample size for the training set. This is a common characteristic of medical device submissions, as the focus is on validation (test set performance) rather than the proprietary details of model training (if applicable to this type of assay, though molecular assays often rely on established biochemical principles rather than "training" in the machine learning sense). The development of the reformulated probe reagent would have involved laboratory optimization and characterization experiments, which are analogous to a "training" phase.

9. How the Ground Truth for the Training Set Was Established

Since this is a molecular diagnostic assay and not an AI/ML product requiring extensive "training" data, the concept of "ground truth for the training set" isn't directly applicable in the same way. The development process for the reformulated probe would have involved:

• Understanding the genetic variants: Identifying the specific mutations in the C. trachomatis variants (e.g., FI-nvCT) that caused detection issues with the previous probe.
• Rational design: Designing new probe sequences that would bind effectively to both the original target and the new variants.
• Iterative testing and optimization: Extensive laboratory testing of various probe formulations using cultured organisms, synthetic nucleic acids, and potentially some clinical samples to ensure desired performance (sensitivity, specificity, variant detection) during the development phase. This iterative process, guided by known target sequences and laboratory results, serves as the "ground truth" for optimizing the assay components.

In summary, the submission demonstrates that the modified Aptima Combo 2 Assay maintains or improves its performance compared to the predicate device, particularly in its ability to detect emerging CT variants, without compromising its overall accuracy or introducing new risks. The studies are analytical and comparative, appropriate for a molecular diagnostic device modification rather than an imaging AI solution.

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The Aptima Combo 2® Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal disease using the Panther® System as specified. On the Panther System, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, vaginal, throat, rectal, and male urethral swab specimens, clinician-collected gynecological specimens collected in the PreservCyt® Solution, patient-collected vaginal swab specimens,1 and female and male urine specimens.

The Aptima Combo 2® Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the Tigris® DTS® Automated Analyzer or semi-automated instrumentation as specified. The assay may be used to test the following specimens from symptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; and female and male urine specimens. The assay may be used to test the following specimens from asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; patient-collected vaginal swab specimens1; and female and male urine specimens. The assay is also intended for use with the testing of gynecological specimens, from both symptomatic and asymptomatic patients, collected in the PreservCyt® Solution.

The Aptima Trichomonas vaginalis Assay is an in vitro qualitative nucleic acid amplification test (NAAT) for the detection of ribosomal RNA (rRNA) from Trichomonas vaginalis to aid in the diagnosis of trichomoniasis using the Panther System. The assay may be used to test the following specimens from symptomatic or asymptomatic women: clinician-collected endocervical swabs. clinician-collected vaginal swabs, and specimens collected in PreservCyt Solution.

The Aptima Trichomonas vaginalis Assay is an in vitro qualitative nucleic acid amplification test (NAAT) for the detection of ribosomal RNA (rRNA) from Trichomonas vaginalis to aid in the diagnosis of trichomoniasis using the Tigris® DTS® System. The assay may be used to test the following specimens from symptomatic or asymptomatic women: clinician-collected endocervical swabs, clinician-collected vaginal swabs, female urine specimens, and specimens collected in PreservCyt Solution.

The clearance of this Special 510(k) application will allow the use of a Ready-Made Reagent format for the Aptima Combo 2 assay (AC2) and the Aptima Trichomonas Vaginalis assay (ATV) on the Tigris and Panther systems. The use of Ready-Made Reagent assays does not change the principles of procedure, intended use, or primary technological characteristics.

Currently, each of the AC2 and ATV Amplification, Enzyme, and Probe reagents are provided in two parts: a lyophilized reagent (cake form) and a reconstitution solution (liquid form). Per the instructions provided in the respective assay's package inserts, the customers are instructed to prepare the reagents by reconstituting each reagent by combining the bottles of lyophilized reagent with the reconstitution solution and mixing reagents manually prior to placing on the Panther or Tigris system. Hologic developed "Ready Made Reagents" (RMRs), which are liquid format or pre-reconstituted Amplification, Enzyme, and Probe reagents available for customers to procure in the 250-Test Kit size available for use on both the Tigris and Panther systems.

Changes to the user interface are minimal as the RMRs are identical to the lyophilized reagents once they have been reconstituted at the laboratory. In order to prepare the current format reagents (lyophilized format), the laboratory personnel pairs each reconstitution solution (Amplification, Enzyme, and Probe) with its respective lyophilized reagent. Using the RMR format, the customer eliminates the reconstitution step and is only required to bring the three reagents to room temperature following the same process currently done for the previously reconstituted reagents. All subsequent steps by the operator are unchanged. All assay principles and processing steps on the Panther or Tigris systems remain unchanged. There are no changes to the instrument hardware or software based on this change.

The provided text describes a 510(k) summary for new "Ready-Made Reagents" (RMRs) for the Aptima Combo 2 Assay and Aptima Trichomonas Vaginalis Assay, designed to simplify reagent preparation for laboratory personnel. The submission aims to demonstrate substantial equivalence to previously cleared predicate devices.

Here's an analysis of the acceptance criteria and study proving the device meets them, based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state "acceptance criteria" in a numerical table format with pre-defined thresholds. However, the implicit acceptance criteria for demonstrating substantial equivalence are based on comparability to the predicate devices, particularly in the analytical performance studies (Limit of Detection and Intended Use) and clinical performance studies. The goal is to show that the RMR format performs equivalently to the existing lyophilized format.

Implicit Acceptance Criteria (based on study design and conclusions):

2. Sample Size Used for the Test Set and Data Provenance

• Intended Use Study:
  • The document mentions "negative and positive panels" and "CT positive, GC positive, and CT/GC dual positive panels" but does not specify the exact number of samples/panels used for each test.
  • Data provenance is implicitly laboratory-generated (panels with known analytes), not clinical patient samples for this specific study section.
• Limit of Detection Study:
  • The document mentions using "stocks of CT and GC organisms in negative clinical liquid pap specimens" and "stocks of TV organisms in negative clinical liquid pap specimens".
  • Does not specify a sample size (number of specimens/replicates) explicitly for the LoD determination.
  • Data provenance appears to be laboratory-prepared samples using clinical specimen matrices.
• Clinical Performance Study:
  • Sample Size: Three hundred (300) remnant clinical swab specimens.
  • Data Provenance: Retrospective, clinical samples ("remnant clinical swab specimens"). The country of origin is not specified but implicitly within the US as this is an FDA submission.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Not applicable in the traditional sense of image-based AI studies using human expert consensus.
• For these in vitro diagnostic (IVD) assays, the "ground truth" for the analytical and clinical studies is established through:
  • Known concentrations in prepared panels (Intended Use, LoD).
  • Reference assay results (the "current AC2 assay" or "current ATV assay" is used as the baseline/reference result in the clinical comparability study). This assumes the predicate device's performance is the established truth for comparison.

4. Adjudication Method for the Test Set

• Not applicable in the context of human expert adjudication for a test set.
• The "adjudication" is essentially the comparison of the RMR assay results against the predicate assay results or against known panel concentrations. Discrepancies would be investigated, but there's no mention of a multi-reader/adjudicator process.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

• No, an MRMC comparative effectiveness study was not done. This type of study is more common for imaging AI devices where human readers interpret images with and without AI assistance.
• This submission is for an in vitro diagnostic (IVD) assay where the device output is typically a qualitative (positive/negative) or quantitative result, not an interpretation by a human reader that is then augmented by AI. The comparison is directly between the new reagent format and the existing reagent format.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

• Yes, in spirit, the studies are analogous to standalone performance. The performance evaluation of the RMR assays (the "device") is measured directly against established analytical and clinical benchmarks (predicate assay performance, known concentrations). There isn't a human-in-the-loop component for the performance evaluation of the assay itself, beyond the manual steps involved in sample preparation or loading described in the "Differences" section. The assay's output (presence/absence of target RNA) is the direct result.

7. The Type of Ground Truth Used

• Analytical Truth: Known concentrations of target organisms in prepared panels (for Intended Use and Limit of Detection studies).
• Comparative Truth: The previously cleared predicate devices (Aptima Combo 2 Assay and Aptima Trichomonas Vaginalis Assay using the lyophilized reagent format) served as the "reference result" or "baseline" for comparison in both analytical and clinical studies. This is a common approach in 510(k) submissions for modifications to existing devices.

8. The Sample Size for the Training Set

• Not applicable. This submission is for a modification to an existing IVD assay (a change in reagent format), not for a machine learning or AI algorithm that requires a "training set." The assays are nucleic acid amplification tests (NAATs) based on established biochemical principles, not on learned patterns from a dataset.

9. How the Ground Truth for the Training Set was Established

• Not applicable as there is no training set for this type of device.

Ask a specific question about this device

The Aptima Combo 2® Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal disease using the Panther® System as specified.

On the Panther System, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, vaginal, throat, rectal and male urethral swab specimens, clinician-collected gynecological specimens collected in the PreservCyt® Solution, patient-collected vaginal swab specimens, and female and male urine specimens.

Clearance of this pre-market application will add extra-genital (throat and rectal) swab specimens as acceptable specimen types using the Aptima Combo 2 assay on the Panther system.

The Aptima Combo 2 Assay combines the technologies of target capture. Transcription-Mediated Amplification (TMA), and Dual Kinetic Assay (DKA). Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the Aptima Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deoxyadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification.

Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Aptima Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded chemiluminescent DNA probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The labeled DNA probes combine with amplicon to form stable RNA:DNA hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer, and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection reaction for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

The Aptima Combo 2 assay has been designed for and validated on the Panther system. The Panther system is an integrated hardware and software system that together with the Aptima Combo 2 assay fully automates all the steps necessary to perform the assay from sample preparation through amplification of nucleic acid, detection, data reduction and amplicon inactivation.

Here's a summary of the acceptance criteria and study details for the Aptima Combo 2 Assay:

Aptima Combo 2 Assay (Panther System) - Acceptance Criteria and Study Details

The Aptima Combo 2 Assay is a target amplification nucleic acid probe test for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) using the Panther System. This submission specifically addresses the addition of extra-genital (throat and rectal) swab specimens as acceptable specimen types.

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly stated as numerical thresholds in the provided text. However, the study aims to demonstrate "comparable performance to the predicate device" and support a "substantial equivalence decision." The clinical study evaluates the device's sensitivity and specificity against an "anatomic site infected status (ASIS)" established by reference NAATs.

Based on the provided tables (Table 10 and Table 11), the reported device performance for sensitivity and specificity (with 95% Confidence Intervals) are as follows:

Note: The superscripts in the table refer to footnotes in the original document regarding equivocal results and their impact on recalculating sensitivity and specificity.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size (Evaluable Subjects): 2591 subjects had at least one sample type tested.
  • Throat Samples: 2585 for CT performance, 2579 for GC performance (after exclusions).
  • Rectal Samples: 2562 for CT performance, 2569 for GC performance (after exclusions).
• Data Provenance: Prospectively-collected samples from adult (≥18 years) participants seeking STI testing, with or without symptoms, attending nine (9) participating US medical facilities.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

The ground truth (anatomic site infected status - ASIS) was established using reference NAATs. The document does not specify the number or qualifications of experts involved in performing or interpreting these reference NAATs. It suggests that the ASIS was determined algorithmically based on the results of the reference NAATs rather than through human expert consensus, stating: "Subjects were categorized as infected if a positive result occurred in at least two reference NAATs, and as not infected if at least 2 of the reference results were negative."

4. Adjudication Method for the Test Set

The adjudication method for establishing the ASIS (ground truth) was a 2+1 rule based on reference NAATs.

• Infected: Positive result in at least two reference NAATs.
• Not Infected: Negative result in at least two reference NAATs.
• Tie-breaker: A third reference NAAT was used if the first two reference results were discordant.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was mentioned. The study evaluates the standalone performance of the Aptima Combo 2 Assay against a reference standard. It does not compare human readers with AI assistance versus without AI assistance.

6. Standalone Performance Study

Yes, a standalone performance study was conducted. The clinical performance of the Aptima Combo 2 Assay (algorithm only) was evaluated against the Anatomic Site Infected Status (ASIS) for each specimen type-organism combination. The results for sensitivity and specificity presented in Tables 10 and 11 represent the standalone performance of the device.

7. Type of Ground Truth Used

The ground truth used was "anatomic site infected status (ASIS)" established by multiple reference Nucleic Acid Amplification Tests (NAATs). These reference NAATs were "cleared for the detection of urogenital CT/GC infection and validated for use in rectal swab and throat swab specimens." This is a form of consensus-based ground truth derived from other laboratory tests, not pathology or outcomes data.

8. Sample Size for the Training Set

The document does not provide information on the sample size used for the training set. The provided performance data (sensitivity, specificity) relates to the clinical validation study using prospectively collected samples, which serves as the test set for device clearance. As a diagnostic assay rather than an AI/ML device, a distinct 'training set' in the context of machine learning model development is not typically applicable in the same way. The analytical studies (LoD, cross-reactivity, interfering substances) would inform the assay's development and optimization, but specific training set sizes for algorithmic learning are not detailed.

9. How the Ground Truth for the Training Set was Established

As mentioned above, specific information regarding a 'training set' and its ground truth establishment in the context of machine learning is not provided for this in vitro diagnostic device. The assay development would have involved internal validation and optimization, but the document focuses on the clinical validation (test set) for regulatory submission.

Ask a specific question about this device

The Aptima Combo 2® Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the Panther® System as specified.

On the Panther System, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens, clinician-collected gynecological specimens collected in the PreservCyt® Solution, patient-collected vaginal swab specimens, 1 and female and male urine specimens.

1 Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The vaginal and multitest swab specimen collection kits are not for home use.

Clearance of this pre-market application will add female urine as an acceptable specimen type using the Aptima Combo 2 assay on the Panther system.

The Aptima Combo 2 Assay combines the technologies of target capture, Transcription-Mediated Amplification (TMA), and Dual Kinetic Assay (DKA). Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the Aptima Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deoxyadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification.

Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Aptima Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded chemiluminescent DNA probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The labeled DNA probes combine with amplicon to form stable RNA:DNA hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer, and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection reaction for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

The Aptima Combo 2 assay has been designed for and validated on the Panther system. The Panther system is an integrated hardware and software system that together with the Aptima Combo 2 assay fully automates all the steps necessary to perform the assay from sample preparation through amplification of nucleic acid, detection, data reduction and amplicon inactivation.

Here's an analysis of the provided text regarding the Aptima Combo 2 Assay (Panther System), focusing on acceptance criteria and the supporting study:

The provided document describes a 510(k) premarket notification for the Aptima Combo 2 Assay (Panther System) to add female urine as an acceptable specimen type. The study aimed to demonstrate substantial equivalence to the predicate device, which already included other specimen types.

1. Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state "acceptance criteria" in a table format with numerical targets. Instead, it presents the Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) of the device compared to a Composite Comparator Algorithm (CCA) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in female urine samples. For regulatory clearance, these performance metrics are implicitly the acceptance criteria; the observed performance must be deemed sufficient for the intended use and comparable to similar marketed devices.

Based on the performance tables provided, here's a summary of the reported device performance, which likely served as the basis for acceptance:

Reported Performance of Aptima Combo 2 Assay (Panther System) for Female Urine

Note: The confidence intervals provide the range within which the true PPA/NPA is likely to fall. For asymptomatic GC, the PPA has a wider confidence interval due to a smaller number of positive cases.

2. Sample Size and Data Provenance

• Sample Size for Test Set:
  • Total subjects initially enrolled: 2640
  • Subjects with valid Aptima Combo 2 Assay results on Panther System: 2581
  • Evaluable subjects for performance (conclusive CCA status): 2580
  • Final Sample Size for CT performance: 2572 (1379 symptomatic, 1193 asymptomatic) after accounting for equivocal results and non-evaluable subjects.
  • Final Sample Size for GC performance: 2579 (1383 symptomatic, 1196 asymptomatic) after accounting for equivocal results and non-evaluable subjects.
• Data Provenance: Retrospective study.
  • Specimens originated from women enrolled in a previously completed prospective study.
  • The study participants (women) were enrolled from 17 geographically and ethnically diverse US clinical sites, including family planning, academic centers, and public health clinics.

3. Number of Experts and Qualifications for Ground Truth

The document does not specify the number of experts used to establish the ground truth or their qualifications. The ground truth (Composite Comparator Algorithm, CCA) was established using multiple FDA-cleared NAATs, not directly by human experts adjudicating individual cases based on clinical information or pathology.

4. Adjudication Method for the Test Set

The adjudication method used to establish the Composite Comparator Algorithm (CCA) for the ground truth was:

• 2 out of 3 rule: When 2 out of 3 FDA-cleared CT/GC NAATs were positive, the CCA was considered positive. When 2 out of 3 NAATs were negative, the CCA was considered negative.
• Tie-breaker: If the results from the initial two comparator NAATs did not determine the CCA, a third FDA-cleared CT/GC NAAT was performed using remnant urine samples to determine the CCA.

This is a form of consensus-based ground truth, but using other diagnostic tests rather than direct clinical expert consensus.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was done. This study evaluated the standalone performance of a diagnostic assay (Aptima Combo 2 Assay) against a reference standard (CCA), not the effect of AI assistance on human readers.

6. Standalone Performance

Yes, a standalone performance study was done. The entire clinical study described evaluates the performance of the Aptima Combo 2 assay on the Panther System (the algorithm/device itself) directly against the Composite Comparator Algorithm (CCA) without human interpretation as part of the primary outcome measure. The PPA and NPA values reported are the standalone performance metrics.

7. Type of Ground Truth Used

The ground truth used was a Composite Comparator Algorithm (CCA), which was derived from the results of multiple (up to 3) FDA-cleared nucleic acid amplification tests (NAATs). While this is a common method for establishing a "gold standard" in diagnostic test evaluations, it is not direct pathology, clinical outcomes data, or expert consensus in the traditional sense of clinicians reviewing patient records or images. It establishes the "truth" based on a highly sensitive and specific panel of existing diagnostic tools.

8. Sample Size for the Training Set

The document does not provide information on the sample size for a training set. This is a diagnostic assay (a lab test), not an AI/machine learning model in the typical sense that would require a separate, explicit "training set" for model parameters. The "development" or "training" of such an assay involves reagent formulation, assay protocol optimization, and establishing cut-offs, typically done using characterized samples, but not usually reported with a distinct "training set" size in the same manner as an AI algorithm. The study described is a clinical validation or "test set" evaluation.

9. How the Ground Truth for the Training Set was Established

As mentioned above, there is no explicit "training set" described in the context of this 510(k) submission. The performance study evaluated the device against a CCA, as detailed in point 4 and 7.

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The APTIMA Combo 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the PANTHER System as specified.

On the PANTHER System, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens, clinician-collected gynecological specimens collected in the PreservCyt Solution, patient-collected vaginal swab specimens, and male urine specimens.

Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The vaginal swab specimen collection kit is not for home use.

The APTIMA Combo 2 Assay combines the technologies of target capture, transcriptionmediated amplification (TMA), and dual kinetic assay (DKA).

Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the APTIMA Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deox yadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification.

Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The APTIMA Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded chemiluminescent DNA probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The labeled DNA probes combine with amplicon to form stable RNA:DNA hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer, and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection reaction for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

APTIMA Combo 2® Assay (on PANTHER® System) - Acceptance Criteria and Study Details

The APTIMA Combo 2® Assay is a nucleic acid amplification test for the qualitative detection and differentiation of ribosomal RNA from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease. This 510(k) submission (K132251) specifically focuses on clearing the assay for use with male urine specimens on the PANTHER System.

1. Acceptance Criteria and Reported Device Performance

The provided document details the performance characteristics for male urine, alongside other specimen types, in terms of sensitivity and specificity based on two clinical studies. While explicit "acceptance criteria" in a numeric format (e.g., minimum sensitivity of X%) are not directly stated, the reported performance metrics demonstrate the device's efficacy across various specimen types and symptom statuses. The regulatory approval implies these performance levels met the FDA's requirements for substantial equivalence.

Reported Device Performance for Male Urine (from Table 4 for CT and Table 7 for GC):

Additional detailed performance by symptom status is provided in Table 5 (CT) and Table 8 (GC) and by individual study in Table 6 (CT) and Table 9 (GC).

2. Sample Sizes and Data Provenance for Test Set

The clinical performance data was derived from two multi-center clinical studies conducted in the United States. The data is prospective, as specimens were collected from enrolled symptomatic and asymptomatic individuals for the purpose of the study.

Test Set Sample Sizes:

• Clinical Study 1: Included male urethral swab, vaginal swab, PreservCyt Solution liquid Pap, female endocervical swab, and male urine samples.
  • Male subjects (urine): 580 enrolled. 580 male urine samples were tested.
  • For CT performance analysis, 1799 male urine samples were included (data from Clinical Study 1 and 2 combined, see Table 4).
  • For GC performance analysis, 1797 male urine samples were included (data from Clinical Study 1 and 2 combined, see Table 7).
• Clinical Study 2: Primarily focused on male urine specimens.
  • Male subjects: 1492 enrolled, 1478 male urine samples from non-withdrawn subjects were tested.
  • For CT performance analysis, 1799 male urine samples were included (data from Clinical Study 1 and 2 combined, see Table 4).
  • For GC performance analysis, 1797 male urine samples were included (data from Clinical Study 1 and 2 combined, see Table 7).

A breakdown of male urine samples by study and symptom status for performance evaluation:

• CT (Table 6):
  • Study 1 Asymptomatic: 323 samples
  • Study 2 Asymptomatic: 979 samples
  • Study 2 Symptomatic: 497 samples
  • Total (Study 1 + Study 2) for male urine (Table 4): 1799 samples
• GC (Table 9):
  • Study 1 Asymptomatic: 320 samples
  • Study 2 Asymptomatic: 980 samples
  • Study 2 Symptomatic: 497 samples
  • Total (Study 1 + Study 2) for male urine (Table 7): 1797 samples

3. Number of Experts and Qualifications for Ground Truth

The document does not explicitly state the number of "experts" used to establish the ground truth or their specific qualifications (e.g., radiologist with X years of experience), as this is a diagnostic assay for infectious disease rather than image-based diagnosis.

Instead, the ground truth ("infected status") was established using cleared nucleic acid amplification tests (NAATs). The reference methods are described as:

• "cleared nucleic acid amplification tests (NAATs)" for Clinical Study 1 (male urethral swab, male and female urine, and PreservCyt Solution liquid Pap samples).
• "cleared NAATs" for Clinical Study 2 (male urethral swab and urine samples). Specifically, the infected status algorithm used "urethral swab and urine sample results from one reference CT and GC NAAT and urine sample results from two additional reference CT and GC NAATs to generate four reference results for each analyte."

The qualifications of the individuals performing these reference NAATs are not specified but would presumably be laboratory professionals trained in molecular diagnostics.

4. Adjudication Method for the Test Set

The adjudication method for establishing the "infected status" (ground truth) for the clinical test set was based on an algorithm using multiple reference NAATs.

• Clinical Study 1: "Subjects were categorized as infected if a positive result occurred in each of the two reference NAATs." (See Tables 10, 11, 13, and 14 for specific algorithms for different specimen types and analytes). For female subjects, if positive NAAT results occurred only in urine, they were considered infected for urine evaluation but non-infected for other non-urine specimens.
• Clinical Study 2 (Male Urine): "Subjects were categorized as infected if a positive result occurred in at least two of the reference NAATs." (See Tables 13 and 15).

This method is a form of "consensus" or "composite comparator" ground truth, where multiple established diagnostic tests are used to determine the true infection status in the absence of a single universally accepted gold standard.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was mentioned or performed. This device is an in vitro diagnostic assay, not an imaging device requiring human reader interpretation or AI assistance for human readers. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable here. The assay provides a qualitative result directly.

6. Standalone (Algorithm Only) Performance

Yes, a standalone performance study was conducted. The performance data presented in the tables (Tables 4, 5, 6, 7, 8, 9) for sensitivity, specificity, PPV, and NPV represent the standalone performance of the APTIMA Combo 2 Assay on the PANTHER System, without human-in-the-loop interpretation being part of the result generation. The device itself performs the detection and differentiation of rRNA and provides a qualitative result.

7. Type of Ground Truth Used

The type of ground truth used was "composite comparator" or "reference NAAT consensus". For both clinical studies, the "infected status" was established by comparing results from two or more FDA-cleared nucleic acid amplification tests (NAATs) performed on the same or corresponding samples, rather than pathology (histology), clinical outcomes data, or a single expert's opinion.

8. Sample Size for the Training Set

The document does not explicitly state a separate "training set" sample size in the context of device development. For in vitro diagnostic devices, "training" often refers to internal analytical studies and optimization during development, rather than a distinct clinical "training set" in the way it's used for AI or machine learning models. The provided clinical studies (Clinical Study 1 and Clinical Study 2) represent the validation or test sets used to establish clinical performance.

Analytical sensitivity (Limit of Detection) studies were conducted using dilutions of CT organisms and GC organisms (7). These analytical studies involve controlled samples to determine the detection limits and would be part of the internal development and analytical verification processes, but are not typically referred to as a "training set" in this context.

9. How the Ground Truth for the Training Set Was Established

As noted above, a distinct "training set" with established ground truth in the clinical context is not explicitly described. For the analytical sensitivity studies, the "ground truth" (i.e., known concentration of organisms) was established by spiking known concentrations of CT and GC organisms into various matrices (e.g., Specimen Transport Medium, urine) and testing dilutions. This allows for the determination of the limit of detection (LOD) for the assay.

Ask a specific question about this device

The APTIMA COMBO 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the PANTHER System as specified.

On the PANTHER System, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens, clinician-collected gynecological specimens collected in the PreservCyt Solution, and patient-collected vaginal swab specimens.

The APTIMA Combo 2 Assay combines the technologies of target capture, TMA, and DKA. Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the APTIMA Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deoxyadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification. Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The APTIMA Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded chemiluminescent DNA probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The labeled DNA probes combine with amplicon to form stable RNA:DNA hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer, and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection reaction for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

This FDA 510(k) summary describes the APTIMA Combo 2® Assay on the PANTHER System, a device for in vitro qualitative detection and differentiation of ribosomal RNA from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC). The submission is for clearing the assay for use on the PANTHER System, as it was previously cleared on the TIGRIS System.

Here's an analysis of the provided information:

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria for this device are implicitly tied to the performance characteristics, specifically sensitivity and specificity, as demonstrated in the clinical study. While explicit "acceptance criteria" values for sensitivity and specificity are not directly stated in the summary, the reported performance characteristics are presented with 95% confidence intervals, suggesting that the observed values met predefined thresholds for regulatory approval. The fact that the device received 510(k) clearance further indicates that its performance was deemed acceptable by the FDA.

Table of Performance for APTIMA Combo 2® Assay on the PANTHER System (Clinical Study Results)

Analytical Sensitivity (Limits of Detection):

• CT: Claimed 1 IFU/assay (7.25 IFU/swab, 9.75 IFU/mL, PreservCyt Solution liquid Pap). 100% positivity was observed in samples containing CT concentrations of 0.03 IFU/mL.
• GC: Claimed 50 cells/assay (362 cells/swab, 488 cells/mL PreservCyt Solution liquid Pap). 100% positivity was observed in samples containing GC concentrations of 0.04 CFU/mL.

Within Laboratory Precision (STM matrix, selected rows as an example):

Carryover Study: Overall carryover rate was 0% with a 95% confidence interval of 0-0.1%. This meets an implicit acceptance criterion of negligible or acceptable carryover.

2. Sample Size Used for the Test Set and Data Provenance

The clinical study was a prospective, multicenter clinical study conducted across 7 geographically and ethnically diverse US clinical sites.

Test Set Sample Sizes:

• Male subjects: 580 enrolled, 567 evaluable male urethral swab samples.
  • 18 male urethral swab specimens had final invalid results and were excluded.
• Female subjects: 1332 enrolled.
  • 1319 evaluable vaginal swab samples (clinician-collected/patient-collected combined).
  • 1330 evaluable PreservCyt Solution liquid Pap samples.
  • 1310 evaluable endocervical swab samples.
  • 1 vaginal swab and 1 endocervical swab had final CT equivocal results and were excluded.
  • 1 PreservCyt and 1 endocervical swab had final GC equivocal results and were excluded.
  • Female urine specimens were collected but used as part of the "infected status algorithm" (ground truth definition) rather than directly tested as a primary specimen type for performance against the APTIMA Combo 2 Assay on PANTHER for this 510(k).

Data Provenance: United States (7 US clinical sites). The study was prospective.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

The ground truth was established using an "infected status algorithm" based on results from two specimen types and two reference NAATs (Nucleic Acid Amplification Tests). The specific number and qualifications of experts directly involved in adjudicating the "infected status" or interpreting the reference NAATs are not explicitly stated in the provided text.

However, for a device like this, standard practice for establishing ground truth for NAATs in clinical trials typically involves:

• Use of one or more FDA-cleared and/or highly sensitive and specific reference NAATs.
• Concordance of positive results across multiple tests/specimens to define an "infected status."
• Discrepancies often resolved by a third, highly sensitive method or expert clinical review, though this detail is not provided.

The text states: "Subjects were categorized as infected if a positive result occurred in each of the 2 reference NAATs." This implies a rule-based algorithm for ground truth rather than individual expert adjudication for each case.

4. Adjudication Method for the Test Set

The adjudication method for determining the "infected status" (ground truth) was an algorithm-based approach:

• For male subjects and female subjects, if the positive NAAT results occurred only in the urine specimens and not in the PreservCyt specimens, the subject was categorized as infected; however, for the evaluation of the non-urine specimen types, the specimens were considered non-infected.
• "Subjects were categorized as infected if a positive result occurred in each of the 2 reference NAATs."

This indicates a 2-out-of-2 (or 2+0) concordance rule for positivity to establish infection status. The text doesn't mention a tie-breaking or expert review process if results were discordant between the two reference NAATs, but specimens with "invalid, equivocal, or error results" were retested, and those with final invalid/equivocal results were excluded from analysis.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done.

This device is an in vitro diagnostic test, specifically a nucleic acid amplification test (NAAT). These types of tests are designed to provide a qualitative result (positive/negative) based on an analytical assay run on an automated system, not to be interpreted by human readers in the same way an imaging device or pathology slide might be. Therefore, the concept of "human readers improve with AI vs. without AI assistance" does not apply to this type of device. The "AI" (algorithm) here is the test.

6. Standalone (Algorithm Only) Performance

Yes, standalone performance was done.

The entire clinical study described, including the sensitivity and specificity values provided in Tables 6, 7, 8, 9, 10, and 11, represents the standalone performance of the APTIMA Combo 2 Assay on the PANTHER System. The results are compared against an "infected status algorithm" which serves as the ground truth, not against human interpretation of raw assay data. The device's output is the final diagnostic result.

7. Type of Ground Truth Used

The ground truth used was an algorithm-based "infected status" derived from the results of two reference nucleic acid amplification tests (NAATs) on two different specimen types (e.g., male urethral swab and male urine for males, and PreservCyt and urine for females).

Specifically:

• "Male urethral swab, male and female urine, and PreservCyt samples were tested with cleared nucleic acid amplification tests (NAATs) to establish the infected status."
• "The infected status algorithm used results from two specimen types and two reference NAATs. Subjects were categorized as infected if a positive result occurred in each of the 2 reference NAATs."
• "For female subjects, if the positive NAAT results occurred only in the urine specimens and not in the PreservCyt specimens, the subject was categorized as infected; however, for the evaluation of the non-urine specimen types, the specimens were considered non-infected."

8. Sample Size for the Training Set

The provided text does not specify a sample size for a training set. This document is a 510(k) summary for a diagnostic test, not a submission for a de novo machine learning algorithm that typically requires a distinct training and test set with explicit disclosure of training data. The "device" in this context is the analytical assay and automated system. While the assay itself (APTIMA Combo 2) was developed and validated, the data tables presented relate to the performance evaluation (test set) for the new platform (PANTHER System).

9. How the Ground Truth for the Training Set Was Established

As no explicit training set is detailed for the purpose of a machine learning algorithm in this 510(k) summary, the process for establishing ground truth for a training set is not applicable here. The provided data focuses on the validation of the device on a new platform (PANTHER System) for regulatory clearance, where the clinical study (test set) is the primary evidence for performance.

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The APTIMA COMBO 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis and/or Neisseria gonorrhoeae in clinician-collected endocervical, vaginal and male urethral swab specimens, patientcollected vaginal swab specimens', female and male urine specimens and gynecological specimens collected in the PreservCyt Solution and processed with the Cytyc ThinPrep 2000 System. The assay may be used to test specimens from symptomatic and asymptomatic individuals to aid in the diagnosis of gonococcal and/or chlamydial urogenital disease using the TIGRIS DTS Automated Analyzer or semi-automated instrumentation as specified.

The APTIMA COMBO 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis and/or Neisseria gonorrhoeae.

This document is an FDA 510(k) clearance letter for an in vitro diagnostic device, not an AI/ML medical device. Therefore, the requested information about acceptance criteria, study design, and performance metrics (especially those related to AI/ML such as multi-reader multi-case studies, human reader improvement with AI, or standalone algorithm performance) is not applicable or cannot be extracted from this document.

The document discusses the substantial equivalence of the TIGRIS® DTS® GEN-PROBE® APTIMA COMOBO 2® Assay to a legally marketed predicate device for the qualitative detection and differentiation of ribosomal RNA from Chlamydia trachomatis and/or Neisseria gonorrhoeae.

Here's the information that can be extracted, noting the limitations related to your AI/ML specific questions:

1. Table of Acceptance Criteria and Reported Device Performance:

This document does not provide a table of quantitative acceptance criteria (e.g., sensitivity, specificity thresholds) or specific performance metrics (e.g., reported sensitivity, specificity values) from a clinical study. It is a clearance letter acknowledging substantial equivalence to a predicate device, not a detailed performance report. Such data would typically be found in the 510(k) submission itself, not the clearance letter.

2. Sample size used for the test set and the data provenance:

• Test set sample size: Not specified in this document.
• Data provenance: Not specified. Clinical studies supporting clearance typically involve multiple sites, which could be domestic or international, and data could be retrospective or prospective. This information is usually detailed in the submission, not the clearance letter.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

This is irrelevant for an in vitro diagnostic assay like the APTIMA COMBO 2 Assay. The "ground truth" for such assays is typically established by reference laboratory methods (e.g., culture, NAATs) or clinical diagnosis, not by human expert interpretation of images or other data. Therefore, there's no concept of "experts establishing ground truth" in the way described for AI/ML imaging devices.

4. Adjudication method for the test set:

Not applicable for an in vitro diagnostic assay. Adjudication methods (like 2+1 or 3+1) are used to resolve disagreements among human readers, typically in image interpretation, which is not the function of this device.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

Not applicable. This is an in vitro diagnostic test for direct pathogen detection, not an AI-assisted diagnostic imaging or decision support system. Therefore, MRMC studies and the concept of human readers improving with AI assistance are irrelevant to this device.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

The device itself is a standalone assay. It performs the detection of rRNA from Chlamydia trachomatis and/or Neisseria gonorrhoeae without human interpretation influencing the result of the assay itself. However, this is not an "algorithm only" in the sense of an AI model; it's a biochemical assay for pathogen identification. The results are typically interpreted by laboratory personnel. Performance studies for such devices evaluate the accuracy of the device's output against a reference standard.

7. The type of ground truth used:

While not explicitly stated in this clearance letter, for in vitro diagnostic assays detecting pathogens, the ground truth is typically established by:

• Culture: For bacterial infections like N. gonorrhoeae.
• Other highly sensitive and specific Nucleic Acid Amplification Tests (NAATs): Often used as a gold standard or "truth" for comparison, especially for C. trachomatis where culture is difficult.
• Clinical diagnosis: Supported by other laboratory findings and patient symptoms.

8. The sample size for the training set:

Not applicable. This document refers to a molecular diagnostic assay, not an AI/ML model that requires a training set. The development of such assays involves analytical studies (assay optimization, limit of detection, cross-reactivity) and clinical studies (evaluating performance on patient samples), but there's no "training set" in the context of machine learning.

9. How the ground truth for the training set was established:

Not applicable, as there is no "training set" in the AI/ML sense for this device. Ground truth in the context of assay development is established through rigorous analytical and clinical validation against established reference methods.

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The APTIMA Combo 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) in clinician-collected endocervical, vaginal, and male urethral swab specimens, patientcollected vaginal swab specimens*, and female and male urine specimens. The assay is also intended for use with testing of gynecological specimens collected in the PreservCyt Solution and processed with the Cytyc ThinPrep 2000 System. The assay may be used to test specimens from symptomatic and asymptomatic individuals to aid in the diagnosis of gonococcal and/or chlamydial urogenital disease.

*Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The vaginal swab specimen collection kit is not for home use.

The GEN-PROBE® APTIMA® Specimen Transfer Kit is only for use with GEN-PROBE APTIMA assays for the detection of Chlamydia trachomatis and/or Neisseria gonorrhoeae. The GEN-PROBE APTIMA Specimen Transfer Kit allows for APTIMA Assay testing of gynecological specimens collected and processed by the Cytyc ThinPrep 2000 Processor according to the instructions provided.

Clearance of this premarket notification extends the clinical performance claims of the commercially available GEN-PROBE APTIMA Combo 2 Assay to include PreservCyt liquid Pap specimens (collected and processed by the Cytyc ThinPrep 2000 Processor) as acceptable testing specimens. The ancillary kit formulated for this specific application is the GEN-PROBE APTIMA Specimen Transfer Kit. The components of the APTIMA Specimen Transfer Kit include: (1) a transport tube containing transport media with a penetrable cap and (2) specific instructions for use regarding decontamination and specimen processing procedures. The APTIMA Specimen Transfer Kit may only be used in conjunction with GEN-PROBE APTIMA Assays for the detection of Chlamydia trachomatis and/or Neisseria gonorrhoeae..

The GEN-PROBE® APTIMA COMBO2® Assay performance has been evaluated through a multi-center clinical study.

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample size used for the test set and the data provenance:

• Test Set Sample Size: 1,647 female subjects (1,288 asymptomatic, 359 symptomatic).
• Data Provenance: Prospective multi-center clinical study conducted in the United States (as implied by the FDA submission and the company's US address). The study involved subjects attending OB/GYN, family planning, public health, women's, and STD clinics.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

• The document does not explicitly state the number or qualifications of experts used to establish the ground truth. Instead, the ground truth was established by a patient infected status algorithm based on the results of two commercially-available reference NAATs performed on endocervical swab specimens. This implies that the ground truth was determined by laboratory testing protocols rather than direct expert consensus on each individual case.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

• Adjudication Method: "None" in the sense of expert human adjudication. The ground truth for the "patient infected status" was based on concordant positive results from two reference NAATs (APTIMA Combo 2 Assay and APTIMA CT Assay for C. trachomatis; APTIMA Combo 2 Assay and APTIMA GC Assay for N. gonorrhoeae). If the two reference NAATs disagreed or were negative, the patient was designated as non-infected. This is a form of algorithmic adjudication rather than human expert adjudication.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

• No, a multi-reader multi-case (MRMC) comparative effectiveness study was NOT done. This study evaluates a laboratory diagnostic assay (APTIMA Combo 2 Assay) and does not involve human readers interpreting images or data to be assisted by AI. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not apply here.

6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:

• Yes, this was effectively a standalone performance study for the device. The APTIMA Combo 2 Assay, as a nucleic acid amplification test, functions as an algorithm-only device (an in vitro diagnostic test kit that produces a qualitative result based on amplification and detection of rRNA). Its performance was evaluated against a defined ground truth without direct human interpretation in a diagnostic loop that would affect its result. The assay generates a direct qualitative result (positive/negative) which is then used by clinicians for diagnosis.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

• Algorithm-based Patient Infected Status (Reference NAATs):
  • For C. trachomatis: A patient was considered infected if both the APTIMA Combo 2 Assay and the APTIMA CT Assay (both performed on endocervical swabs) returned positive results.
  • For N. gonorrhoeae: A patient was considered infected if both the APTIMA Combo 2 Assay and the APTIMA GC Assay (both performed on endocervical swabs) returned positive results.
  • A non-infected patient was established if the results from the two reference NAATs disagreed or were negative. This is effectively a composite reference standard based on other validated diagnostic tests.

8. The sample size for the training set:

• The document does not explicitly describe a separate training set for the APTIMA Combo 2 Assay in the context of this submission. The product being submitted for clearance is an existing assay (APTIMA Combo 2 Assay (K003395)) and the clearance sought is an extension of its clinical performance claims to include PreservCyt liquid Pap specimens.
• The non-clinical (analytical) studies (Limit of Detection, Specificity, Interference, Recovery, Stability, Precision) likely involved internal development and optimization, which could be considered an implicit "training" or development phase. However, a distinct "training set" in the machine learning sense is not mentioned. The clinical study described is solely for validation/testing of the assay's performance with the new specimen type.

9. How the ground truth for the training set was established:

• As a distinct training set is not explicitly mentioned for this 510(k) submission, the method for establishing its ground truth is also not detailed. The ground truth for the non-clinical (analytical) studies typically involved controlled laboratory experiments using known concentrations of organisms and interference substances, with results verified by standard laboratory methods.

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The APTIMA Combo 2 Assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal ribonucleic acid (rRNA) from Chlamydia trachomatis and/or Neisseria gonorrhoeae in clinician-collected endocervical, vaginal, and male urethral swab specimens, patient-collected vaginal swab specimens* and male and female urine specimens. The assay may be used to test specimens from symptomatic and asymptomatic individuals to aid in the diagnosis of gonococcal and/or chlamydial urogenital disease.

*Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The vaginal swab specimen collection kit is not for home use.

The APTIMA Vaginal Swab Specimen Collection Kit is for use with the APTIMA Assays for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae. The APTIMA Vaginal Swab Specimen Collection Kit is intended to be used for clinician and patient collection of vaginal swab specimens according to the instructions provided. Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The APTIMA Vaginal Swab Specimen Collection Kit is not for home use.

Clearance of this premarket notification extends the clinical performance claims of the commercially available GEN-PROBE APTIMA Combo 2 Assay to include clinician-collected and patient-collected vaginal swabs (in a medical setting) as acceptable testing specimens. The ancillary kit formulated for this specific application is the GEN-PROBE APTIMA Vaginal Swab Specimen Collection Kit. The components of the APTIMA Vaginal Swab Specimen Collection Kit include: (1) a sterile swab for the collection of vaginal specimens and (2) a transport tube containing transport media with a penetrable cap.

The APTIMA Vaginal Swab Specimen Collection Kit is for use with the APTIMA Assays for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae. The APTIMA Vaginal Swab Specimen Collection Kit is intended to be used for clinician and patient collection of vaginal swab specimens according to the instructions provided. The APTIMA Vaginal Swab Specimen Collection Kit not for home use.

The APTIMA Combo 2 Assay incorporates the technologies of target capture, in vitro nucleic acid amplification, and hybridization of target amplicons with acridinium ester-labeled DNA probes to specifically detect and differentiate both C. trachomatis and N. gonorrhoeae nucleic acids in clinical specimens. GEN-PROBE's proprietary technologies are combined in this product to allow qualitative detection of C. trachomatis rRNA and N. gonorrhoeae rRNA.

Here's a breakdown of the acceptance criteria and study details for the GEN-PROBE® APTIMA® Combo 2 Assay, based on the provided text:

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied through the sensitivity and specificity values reported, which are compared against a "patient infected status algorithm" as the ground truth. While explicit numerical acceptance thresholds are not stated in the provided text (common in older 510(k) summaries which often relied on substantial equivalence to predicate devices), the study aims to demonstrate high performance.

Chlamydia trachomatis (CT)

Neisseria gonorrhoeae (NG)

2. Sample Size Used for the Test Set and Data Provenance

The study was a multi-center clinical study involving 1,464 symptomatic and asymptomatic female subjects.

• Sample Size:
  • For CT analysis: 2,868 vaginal swab test results.
  • For NG analysis: 2,867 vaginal swab test results.
  • These numbers represent the combined results from patient-collected and clinician-collected vaginal swabs.
• Data Provenance: The data was collected from subjects attending STD, OB/GYN, teen, and family planning clinics. The text does not explicitly state the country of origin, but given it's a US FDA submission, it's highly likely to be a prospective multi-center clinical study conducted in the United States.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The ground truth was established using an algorithm, not directly by human experts interpreting images or test results. Therefore, the concept of "number of experts" and "qualifications of those experts" as typically applied to expert review in imaging studies, does not directly apply here. The accuracy of the reference standard relies on the performance of the commercially available NAATs used.

4. Adjudication Method for the Test Set

The adjudication method for establishing the patient infected status was algorithmic (rule-based):

• Subjects were considered infected with C. trachomatis or N. gonorrhoeae if two of the four reference NAAT results were positive (one specimen testing positive in each NAAT: APTIMA Combo 2 Assay and another commercially available NAAT, using endocervical swab and urine specimens).
• Subjects were considered non-infected if less than two reference NAAT results were positive.

This method uses concordant results from multiple tests/specimens to define the "true" infection status.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. This study is for an in vitro diagnostic (IVD) assay detecting biomarkers, not an AI-assisted diagnostic imaging device that involves human reader interpretation. Therefore, the concept of human readers improving with AI vs. without AI assistance does not apply.

6. Standalone Performance Study

Yes, a standalone performance study was done for the algorithm (the APTIMA Combo 2 Assay). The entire clinical study described evaluates the performance of the device on its own, comparing its results from vaginal swab specimens to the defined patient infected status algorithm. The reported sensitivity and specificity values are for the device operating as a standalone diagnostic tool for vaginal swab specimens.

7. Type of Ground Truth Used

The ground truth used was an algorithmic consensus based on multiple reference nucleic acid amplification tests (NAATs). Specifically:

• Endocervical swab and urine specimen results from the commercially-available APTIMA Combo 2 Assay and another commercially-available NAAT were used.
• Infection status was determined by requiring a positive result from both reference NAATs.
• Culture was not used as a reference test for this specific study, as the APTIMA Combo 2 Assay had previously been evaluated against culture for other specimen types (as per K003395).

8. Sample Size for the Training Set

The document does not provide information regarding a distinct "training set" sample size. For an IVD assay like this, development typically involves analytical validation (sensitivity, specificity, interference etc.) and then clinical validation with a distinct set of clinical samples. The analytical studies (like analytical sensitivity, specificity, recovery, interference) might be considered analogous to early-stage development/testing, but a formal "training set" in the machine learning sense is not explicitly mentioned or typically applicable for this type of assay in this context. The clinical study described served as the primary performance evaluation.

9. How the Ground Truth for the Training Set Was Established

As noted above, the concept of a separate "training set" with established ground truth in the machine learning context is not detailed. The primary clinical study used the algorithmic consensus described in point 4 as its ground truth for evaluating the device's performance.

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