(521 days)
The Visby Medical Sexual Health Click Test is a single-use (disposable), fully-integrated, automated Polymerase Chain Reaction (PCR) in vitro diagnostic test intended for use in point of-care or clinical laboratory settings for the rapid detection and differentiation of DNA from Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in seff-collected female vaginal swab specimens using the Visby Medical Sexual Health Vaginal Specimen Collection Kit in a health care setting. The test results are to aid in the diagnosis of symptomatic infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.
The test system includes the Visby Medical Sexual Health Click device, the Visby Medical power supply, the Visby Medical Vaginal Collection kit, and fixed-volume transfer pipettes. The device processes a vaginal swab sample by automatically performing all steps required to complete lysis, polymerase chain reaction, and amplicon detection.
The patient uses the Visby Medical Vaginal Collection Kit to self-collect a vaginal specimen with the provided flocked swab, and then the patient elutes the specimen into the Visby Medical Collection Media. The test operator transfers the collection media containing the patient specimen into the sample port of the device using the provided fixed-volume pipette where it rehydrates a lyophilized internal process control. The sample enters a lysis module, where the DNA of the sample and the internal process control are extracted using a combination of chemical lysis and high temperature. The extracted DNA enters a mixing chamber where it rehydrated lyophilized PCR reagents, followed by thermocycling to amplify target DNA. If present, the amplified pathogen target (CT, NG, and/or TV) and internal process control hybridize to specific probes located on a flow channel. Detection of the target-specific PCR product is accomplished via an enzyme-linked colorimetric assay using streptavidin bound horseradish peroxidase (HRP) and a colorimetric substrate that forms a purple precipitate. Test results can be expected in approximately 30 minutes: a green check mark will appear, and a purple color will appear in the "Control" spot, indicating a valid test. A purple spot adjacent to "Chlamydia," "Gonorrhoeae," and/or "Trichomonas" signifies the presence of amplified CT, NG, and/or TV DNA in the sample. Tests with invalid results due to an error (indicated by a red X status light) or failure to develop a purple spot in the "Control" spot, are retested with a new Visby device.
The Visby Medical Sexual Health Click Test is an automated Polymerase Chain Reaction (PCR) in vitro diagnostic test for the rapid detection and differentiation of DNA from Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) in self-collected female vaginal swab specimens.
Here's an analysis of its acceptance criteria and the study that proves its performance:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly defined by the clinical performance observed in the study, aiming for high sensitivity and specificity. The reported device performance is based on the achieved Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) or Sensitivity and Specificity against a Composite Comparator Result (CCR) or Patient Infected Status (PIS).
| Target Organism | Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (95% CI) |
|---|---|---|---|
| Chlamydia trachomatis (CT) | Overall PPA | High (e.g., >90%) | 97.4% (93.5-99.0%) |
| Overall NPA | High (e.g., >90%) | 97.8% (96.9-98.4%) | |
| Neisseria gonorrhoeae (NG) | Overall PPA | High (e.g., >90%) | 97.8% (88.4-99.6%) |
| Overall NPA | High (e.g., >90%) | 99.1% (98.5-99.4%) | |
| Trichomonas vaginalis (TV) | Overall Sensitivity | High (e.g., >90%) | 99.3% (96.0-99.9%) |
| Overall Specificity | High (e.g., >90%) | 96.7% (95.8-97.5%) |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size:
- CT: 1774 subjects
- NG: 1786 subjects
- TV: 1765 subjects
- Initially, 1899 subjects were enrolled, 1881 were eligible, and 1789 were included in the data analysis.
- Data Provenance: The study was conducted at 14 clinical sites geographically distributed across the United States. The study subjects were prospectively enrolled females.
3. Number of Experts Used to Establish Ground Truth and Their Qualifications
- The document does not specify the number of experts explicitly used to establish the ground truth.
- The ground truth was established by a Composite Comparator Result (CCR) for CT and NG, and a Patient Infected Status (PIS) algorithm for TV, which were comprised of three FDA-cleared NAAT assays.
- The qualifications of the individuals interpreting the results of these FDA-cleared NAAT assays are not explicitly stated, but it can be inferred that they would be trained laboratory personnel given the nature of NAAT testing.
4. Adjudication Method for the Test Set
- Adjudication Method: For all three organisms (CT, NG, TV), the ground truth (CCR/PIS) was determined as follows:
- A study participant was considered infected if a positive result was reported from two of the three FDA-cleared NAAT tests.
- If the test results of the first two NAATs were discordant (one positive, one negative), the CCR/PIS was determined by the third NAAT. This is often referred to as a "2 out of 3" or "tie-breaker" adjudication method.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No MRMC comparative effectiveness study was done in the context of human readers improving with or without AI assistance. This device is a fully-automated in vitro diagnostic test, and the clinical study evaluated the device's performance directly against a laboratory-based ground truth, not human reader performance.
- However, a reproducibility study was conducted with "untrained users" (non-laboratorians) in CLIA waived settings, to assess the device's performance when used by typical healthcare professionals in such environments. This indirectly assesses the device's usability and reliability in a real-world setting where "human readers" (the operators) process samples and interpret simple visual results (green check mark for valid, purple spots for positive). The study demonstrated robust reproducibility and that untrained users could perform and interpret results accurately, but it wasn't a comparative effectiveness study of human reader improvement.
6. Standalone Performance Study (Algorithm Only Without Human-in-the-Loop Performance)
- Yes, the clinical performance described in section H is a standalone performance study (device only without human-in-the-loop performance influencing the result generation). The device processes a vaginal swab sample fully-integrated and automatically, performing lysis, PCR, and amplicon detection, and then provides a visual result (a green check mark for valid and purple spots for positive). The study evaluated how this automated device's results compared to the established ground truth.
- While human operators handled the samples and initiated the test, the test interpretation is designed to be straightforward and automatic (visual detection of colored spots), making the clinical performance metrics largely reflective of the algorithm's standalone capability to detect the presence of pathogens. The reproducibility study explicitly confirmed that "untrained users can perform the test and interpret the results accurately."
7. Type of Ground Truth Used
- The ground truth used was a Composite Comparator Result (CCR) for CT and NG, and a Patient Infected Status (PIS) algorithm for TV.
- This ground truth was derived from the results of three FDA-cleared NAAT (Nucleic Acid Amplification Test) assays. This is a common and robust method for establishing ground truth in molecular diagnostics, as NAATs are highly sensitive and specific.
8. Sample Size for the Training Set
- The document focuses on the validation of the device through non-clinical and clinical studies. It does not specify the sample size for a training set.
- As an in vitro diagnostic (IVD) device, its development likely involves extensive internal optimization and testing (which could be considered analogous to "training" in the context of AI/ML, though this device is PCR-based with colorimetric detection, not explicitly a machine learning algorithm) using characterized samples and analytical performance studies (Limit of Detection, Inclusivity, Cross-Reactivity, etc.). These analytical studies serve as a rigorous "training" and development phase, but specific "training set sizes" as might be reported for a machine learning model are not applicable or provided here.
9. How the Ground Truth for the Training Set Was Established
- Since a specific "training set" with established ground truth as in AI/ML model development is not explicitly mentioned or applicable to this type of PCR-based diagnostic, this question cannot be directly answered from the provided text.
- However, the analytical studies (LoD, Inclusivity, Cross-Reactivity, Competitive Interference, Interfering Substances, Reproducibility) described in section G involve using well-characterized organisms (known strains/serovars with specified concentrations) spiked into negative clinical vaginal sample matrix. The "ground truth" for these analytical samples is the known presence/absence and concentration of the spiked organisms. This rigorous analytical characterization serves to ensure the robust performance of the assay.
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Visby Medical, Inc. Beth Lingenfelter Clinical and Regulatory Affairs 3010 N. First Street San Jose, California 95134
August 26, 2021
Re: K200748
Trade/Device Name: Visby Medical Sexual Health Click Test Regulation Number: 21 CFR 866.3393 Regulation Name: Nucleic acid detection system for non-viral microorganism(s) causing sexually transmitted infections. Regulatory Class: Class II Product Code: OEP, MKZ, LSL, OUY Dated: June 24, 2021 Received: June 25, 2021
Dear Beth Lingenfelter:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies.combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
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Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531 -542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation -emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely.
Uwe Scherf, M.Sc., Ph.D. Director Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K200748
Device Name Visby Medical Sexual Health Click Test
Indications for Use (Describe)
The Visby Medical Sexual Health Click Test is a single-use (disposable), fully-integrated, automated Polymerase Chain Reaction (PCR) in vitro diagnostic test intended for use in point of-care or clinical laboratory settings for the rapid detection and differentiation of DNA from Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in seff-collected female vaginal swab specimens using the Visby Medical Sexual Health Vaginal Specimen Collection Kit in a health care setting. The test results are to aid in the diagnosis of symptomatic infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.
Type of Use (Select one or both, as applicable)
| Prescription Use (Part 21 CFR 801 Subpart D) | |
|---|---|
| Over-The-Counter Use (21 CFR 801 Subpart C) |
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510(k) Summary
According to the requirements of 21 CFR 807.92, the following information provides sufficient detail to understand the basis for a determination of substantial equivalence
A. Submitter
| Name: | Visby Medical, Inc. |
|---|---|
| Address: | 3010 N. First StreetSan Jose, CA 95134 |
| Phone: | (408) 650 - 8878 |
| Contact: | Beth Lingenfelter |
| Date Prepared: | August 11, 2021 |
B. Device
| Trade Name: | Visby Medical Sexual Health Click Test |
|---|---|
| Classification Name: | Nucleic acid detection system for non-viralmicroorganism(s) causing sexually transmitted infections |
| Regulatory Number: | 866.3393 |
| Regulatory Class: | Class II |
| Product Code: | QEP |
| SubsequentProduct Codes: | MKZ, LSL, OUY |
C. Predicate Devices
The Visby Medical Sexual Health Click Test is substantially equivalent to the Cepheid Xpert® CT/NG Assay and Cepheid Xpert® TV Assay, cleared under K121710 and K151565 on December 27, 2012 and October 16, 2015, respectively.
D. Intended Use
The Visby Medical Sexual Health Click Test is a single-use (disposable), fully-integrated, automated Polymerase Chain Reaction (PCR) in vitro diagnostic test intended for use in point of-care or clinical laboratory settings for the rapid detection and differentiation of DNA from Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in self-collected female vaginal swab specimens using the Visby Medical Sexual Health Vaginal Specimen Collection Kit in a health care setting. The test results are to aid in the diagnosis of symptomatic or asymptomatic infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.
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E. Device Description
The test system includes the Visby Medical Sexual Health Click device, the Visby Medical power supply, the Visby Medical Vaginal Collection kit, and fixed-volume transfer pipettes. The device processes a vaginal swab sample by automatically performing all steps required to complete lysis, polymerase chain reaction, and amplicon detection.
The patient uses the Visby Medical Vaginal Collection Kit to self-collect a vaginal specimen with the provided flocked swab, and then the patient elutes the specimen into the Visby Medical Collection Media. The test operator transfers the collection media containing the patient specimen into the sample port of the device using the provided fixed-volume pipette where it rehydrates a lyophilized internal process control. The sample enters a lysis module, where the DNA of the sample and the internal process control are extracted using a combination of chemical lysis and high temperature. The extracted DNA enters a mixing chamber where it rehydrates lyophilized PCR reagents, followed by thermocycling to amplify target DNA. If present, the amplified pathogen target (CT, NG, and/or TV) and internal process control hybridize to specific probes located on a flow channel. Detection of the target-specific PCR product is accomplished via an enzyme-linked colorimetric assay using streptavidin bound horseradish peroxidase (HRP) and a colorimetric substrate that forms a purple precipitate. Test results can be expected in approximately 30 minutes: a green check mark will appear, and a purple color will appear in the "Control" spot, indicating a valid test. A purple spot adjacent to "Chlamydia," "Gonorrhoeae," and/or "Trichomonas" signifies the presence of amplified CT, NG, and/or TV DNA in the sample. Tests with invalid results due to an error (indicated by a red X status light) or failure to develop a purple spot in the "Control" spot, are retested with a new Visby device.
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F. Substantial Equivalence
The Visby Medical Sexual Health Click Test is substantially equivalent to the Cepheid Xpert CT/NG Assay and the Cepheid Xpert TV Assay, cleared under K121710 and K151565 on December 27, 2012 and October 16, 2015, respectively. Table 1 outlines the similarities and differences between the two system
| Characteristic | Visby MedicalSexual Health Click Test(K200748) | Predicate:Cepheid Xpert CT/NGAssay(K121710) | Predicate:Cepheid Xpert TV Assay(K151565) |
|---|---|---|---|
| Regulation | 21 CFR 866.3393 | 21 CFR 866.3390 | 21 CFR 866.3860 |
| Device Class | Class II | Class II | Class II |
| Technology/Detection | An automated multiplexpolymerase chain reactionwith colorimetric detection | An automated multiplex real-time polymerase chainreaction | An automated real-timepolymerase chain reaction |
| Assay Targets | DNA from Chlamydiatrachomatis (CT), Neisseriagonorrhoeae (NG), andTrichomonas vaginalis (TV) | DNA from Chlamydiatrachomatis (CT) and/orNeisseria gonorrhoeae (NG) | DNA from Trichomonasvaginalis (TV) |
| Specimen Types | Patient-collected vaginalswab | Urine (male and female),endocervical swab, andpatient-collected vaginalswab | Endocervical Swabs FemaleUrinePatient-collected vaginalswab |
| CT Analyte Targets | CT cryptic plasmid DNA | CT genomic DNA | N/A |
| NG AnalyteTargets | NG genomic DNA | NG genomic DNA | N/A |
| TV Analyte Targets | TV genomic DNA | N/A | T. vaginalis genomic DNA |
| Assay Results | Qualitative | Qualitative | Qualitative |
| Collection Kit | Swab collection kit | Urine collection kitSwab collection kit | Urine collection kitSwab collection kit |
| Sample Extraction | Self-contained andautomated after specimensample elution | Self-contained andautomated after specimensample elution and twosingle-dose reagentadditions. | Self-contained andautomated after specimensample elution and twosingle-dose reagentadditions. |
| Instrument System | Visby Medical Sexual HealthClick Test | Cepheid GeneXpertInstrument Systems | Cepheid GeneXpertInstrument Systems |
| Turn-around Time | Approximately 30 minutes toresults. | Approximately 90 minutes toresults. | Approximately 90 minutes toresults. |
| Table 1. Comparison of the Visby Medical Sexual Health Click Test to the Predicate devices |
|---|
| --------------------------------------------------------------------------------------------- |
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visby medical
| Characteristic | Visby MedicalSexual Health Click Test(K200748) | Predicate:Cepheid Xpert CT/NGAssay(K121710) | Predicate:Cepheid Xpert TV Assay(K151565) |
|---|---|---|---|
| Intended Use | The Visby Medical SexualHealth Click Test is a single-use (disposable), fully-integrated, automatedPolymerase Chain Reaction(PCR) in vitro diagnostic testintended for use in point of-care or clinical laboratorysettings for the rapiddetection and differentiationof DNA from Chlamydiatrachomatis, Neisseriagonorrhoeae, andTrichomonas vaginalis inself-collected female vaginalswab specimens collected inVisby Medical CollectionMedia in a health caresetting. The test results areto aid in the diagnosis ofsymptomatic orasymptomatic infectionswith Chlamydia trachomatis,Neisseria gonorrhoeae, andTrichomonas vaginalis. | An automated, multiplexreal-time RT-PCR assay,performed on the GeneXpertInstrument Systems,intended for the in vitroqualitative and differentiationof genomic DNA fromChlamydia trachomatis (CT)and/or Neisseriagonorrhoeae (NG) to aid inthe diagnosis of chlamydialgonorrheal urogenitaldisease. The assay may beused to test the followingspecimens fromasymptomatic andsymptomatic individuals:female and male urine,endocervical swab, andpatient-collected vaginalswab (collected in a clinicalsetting). | The Cepheid Xpert TVAssay, performed on theGeneXpert InstrumentSystems, is a qualitative invitro diagnostic test for thedetection of Trichomonasvaginalis genomic DNA. Thetest utilizes automated real-time polymerase chainreaction (PCR) to detectTrichomonas vaginalisgenomic DNA. The Xpert TVAssay uses female urinespecimens, endocervicalswab specimens, or patient-collected vaginal swabspecimens (collected in aclinical setting). The XpertTV Assay is intended to aidin the diagnosis oftrichomoniasis insymptomatic orasymptomatic individuals. |
| Indication for Use | Asymptomatic andsymptomatic female patients | Asymptomatic andsymptomatic patients | Asymptomatic andsymptomatic patients |
| Assay Controls | Internal sample processingcontrol (SPC). Externalcontrols available. | Internal sample processingcontrol (SPC), sampleadequacy control (SAC),and probe check control(PCC). External controlsavailable. | Internal sample processingcontrol (SPC), sampleadequacy control (SAC),and probe check control(PCC). External controlsavailable. |
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The Visby Medical Vaginal Specimen Collection Kit is substantially equivalent to the following predicate assays:
- Cepheid Xpert Vaginal/Endocervical Specimen Collection Kits
| Table 2. Comparison of the Visby Medical Vaqinal Specimen Collection Kit to the Predicate | ||||
|---|---|---|---|---|
| -- | -- | -- | -- | ------------------------------------------------------------------------------------------- |
| Characteristic | Visby MedicalVaginal Specimen Collection Kit | Cepheid XpertVaginal/Endocervical SpecimenCollection Kits |
|---|---|---|
| Description | A single use package containing anindividually packaged sterile collection swab(for vaginal sampling) and a Visby MedicalCollection Media tube. The collection swabis eluted into the Collection Media tube afterswab sampling. | Contains one individually packaged sterilelarge cleaning swab (for endocervicalsamples) and a package containing anindividually packaged sterile collection swab(for vaginal and endocervical sampling) andan Xpert CT/NG Swab Transport Reagenttube. The collection swab is placed into theTransport Reagent Tube after swabsampling to stabilize the nucleic acid untilsample preparation. |
G. Non-clinical Data
1. Limit of Detection
Limit of Detection (LoD) of the Visby Medical Sexual Health Click Test was determined for CT in elementary bodies per mL (EB/mL), NG in colony forming units per mL (CFU/mL), and TV in trophozoites per mL (troph/mL), from two distinct strains or serovars, seeded into negative clinical vaginal sample matrix (previously determined to be negative for CT, NG, TV). LoD is defined as the lowest concentration of organism that is reliably detected (≥ 95% of tested samples).
The LoD values for each strain were estimated by probit analysis of the results from range-finding studies. The calculated LoDs were verified by testing 20 replicates at the estimated LoD concentration and demonstrating that at least 19 out of 20 replicates were positive. The LoD for each strain is shown in Table 3.
| Organism | LoD | |||
|---|---|---|---|---|
| CT Serovar H (VR-879) | 16.0 EB/mL | |||
| CT Serovar D (VR-885) | 5.9 EB/mL | |||
| NG (ATCC 19424) | 5.7 CFU/mL | |||
| NG (ATCC 49226) | 6.2 CFU/mL | |||
| TV (ATCC 30001, metronidazole susceptible) | 1.2 troph/mL | |||
| TV (ATCC 30238, metronidazole resistant) | 0.24 troph/mL |
Table 3. LoD of CT Serovars. NG strains, and TV strains
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2. Inclusivity
The ability of the Visby Medical Sexual Health Click Test to detect a wide range of target organisms was evaluated by testing 14 serovars of CT, 30 strains of NG, and 15 strains of TV at by spiking them into negative vaginal swab matrix near the assay LoD. For CT, Serovars A, Ba, C, E, F, G, J, K, LGV1 and LGV3 were detected at 32 EB/mL, serovar LGV2 was detected 64 EB/mL and serovar I was detected at 128 EB/mL. For NG, 29 strains were detected at 12.4 cfu/mL and 1 was detected at 24.8 cfu/mL. For TV, all isolates were detected at 2.4 trophs/mL.
3. Cross Reactivity and Microbial Interference
The cross reactivity of the Visby Medical Sexual Health Click Test was evaluated by testing 144 microorganisms seeded into negative vaginal swab matrix at high concentrations (>106 genomic copies/mL for bacteria and >105 genomic copies/mL for viruses). No cross reactivity was observed with the Visby Sexual Health Click Test when testing the organisms listed in Table 4.
In addition, microbial Interference of the same 144 microorganisms on the Visby Medical Sexual Health Click Test was evaluated by testing the same microorganisms spiked into a low positive (3x LoD) sample containing CT, NG and TV. No microbial interference of these microorganisms was observed when testing high concentrations of the organisms listed in the table in a low positive sample.
Additionally, three organisms could not be obtained for direct testing (Bacterial Vaginosis Associated Bacteria 2 (BVAB-2). Meqasphaera type 1, and Dientamoeba fragilis). The sequences of these organisms were analyzed against the Visby Medical Sexual Health Click primer and amplicon sequences using basic local alignment search tool (BLAST). This in-silico analysis did not predict any cross reactivity or microbial interference.
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| Achromobacter xerosis | Cutibacterium acnes | Lactobacillus vaginalis | Pentatrichomonas hominis |
|---|---|---|---|
| Acinetobacter calcoaceticus | Deinococcus radiodurans | Lactococcus lactis | Peptostreptococcusanaerobius |
| Acinetobacter Iwoffii | Derxia gummosa | Legionella pneumophila | Peptostreptococcusproductus(Blautia producta) |
| Actinomyces israelii | Dientamoeba fragilis* | Listeria monocytogenes | Plesiomonas shigelloides |
| Aerococcus viridans | Eikenella corrodens | Megashaera type 1* | Prevotella bivia |
| Aeromonas hydrophila | Elizabethkingiameningoseptica | Micrococcus luteus | Proteus mirabilis |
| Alcaligenes faecalis | Entamoeba histolytica | Mobiluncus curtisii | Proteus vulgaris |
| Arcanobacterium pyogenes | Enterococcus faecalis | Mobiluncus mulieris | Providencia stuartii |
| Atopobium vaginae | Enterococcus faecium | Moraxella lacunata | Pseudomonas aeruginosa |
| Bacteroides fragilis | Enterobacter cloacae | Moraxella osloensis | Pseudomonas fluorescens |
| Bacteroides ureolyticus | Enterococcus raffinosus(avium) | Moraxella (Branhamella)catarrhalis | Pseudomonas putida |
| Bergeriella denitrificans | Erysipelothrixrhusiopathiae | Morganella morganii | Rahnella aquatilis |
| Bifidobacterium adolescentis | Escherichia coli | Mycobacterium smegmatis | Rhodospirillum rubrum |
| Bifidobacterium breve | Fusobacterium nucleatum | Mycoplasma genitalium | Saccharomyces cerevisiae |
| Bifidobacterium longum | Gardnerella vaginalis | Mycoplasma hominis | Salmonella minnesota |
| Blastocystis hominis | Gemella haemolysans | Neisseria elongata (3) | Salmonella typhimurium |
| Brevibacterium linens | Giardia intestinalis | Neisseria cinerea | Serratia marcescens |
| BV associated bacteria(BVAB-2) * | Haemophilus ducreyi | Neisseria subflava | Staphylococcus aureus |
| Campylobacter jejuni | Haemophilus influenzae | Neisseria flavescens (2) | Staphylococcus epidermidis |
| Candida albicans | Herpes simplex virus I | Neisseria perflava | Staphylococcussaprophyticus |
| Candida glabrata | Herpes simplex virus II | Neisseria lactamica (4) | Streptococcus agalactiae |
| Candida parapsilosis | HIV-1 (synthetic RNA) | Neisseria meningitidisserogroup A | Streptococcus bovis |
| Candida tropicalis | Human papilloma virus 16(synthetic DNA) | Neisseria meningitidisserogroup B | Streptomyces griseinus |
| Chlamydophila pneumoniae | Human papilloma virus 16E6/E7 (Transformed cells) | Neisseria meningitidisserogroup C (4) | Streptococcus mitis |
| Chlamydophila psittaci | Kingella dentrificans | Neisseria meningitidisserogroup D | Streptococcus mutans |
| Chlamydia trachomatisLGVII** | Kingella kingae | Neisseria meningitidisserogroup W-135 | Streptococcus pneumoniae |
| Chromobacterium violaceum | Klebsiella aerogenes | Neisseria meningitidisserogroup Y | Streptococcus pyogenes |
| Citrobacter freundii | Klebsiella oxytoca | Neisseria polysaccharea | Streptococcus salivarius |
| Clostridium difficile | Klebsiella pneumoniae | Neisseria subflava | Streptococcus sanguinis |
| Clostridium perfringens | Lactobacillus acidophilus | Neisseria mucosa (3) | Trichomonas tenax |
| Corynebacterium genitalium | Lactobacillus brevis | Neisseria sicca (3) | Ureaplasma urealyticum |
| Corynebacterium xerosis | Lactobacillus crispatus | Pantoea agglomerans | Vibrio parahaemolyticus |
| Cryptococcus neoformans | Lactobacillus jensenii | Paracoccus denitrificans | Yersinia enterocolitica |
Table 4. Microorqanisms Evaluated for Cross-Reactivity and Microbial Interference
- These organisms were not available for direct testing and were evaluated using in-silico analysis
** This organism was correctly positive with the CT assay and negative for NG and TV
(n) number of strains tested
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4. Competitive Interference
The Visby Medical Sexual Health Click test was evaluated for performance in the case of a mixed infection (the presence of multiple target organisms). Each of the target orqanisms (CT, NG, and TV) were seeded into clinical negative vaqinal sample matrix at varying concentrations and then tested in triplicate. Low concentrations were prepared at 3x LoD for the respective organism and high concentrations were prepared at 1 x 106 units/mL. Three (3) replicates were tested for each condition. No competitive interference was observed at the levels tested for all three target organisms.
5. Interfering Substances
The performance of the Visby Medical Sexual Health Click Test in the presence of potentially interfering substances that may be found in a vaginal swab sample was evaluated. Substances were tested in positive (3x LoD) samples for CT, NG, and TV as well as samples negative for CT, NG, and TV. The following substances were tested and found not to interfere with the assay up to the concentrations shown below.
| Substances | Concentration |
|---|---|
| Abreva Cold Sore Cream | 0.25% w/v |
| Biotin | 3.5 µg/mL |
| Menstrual Blood | 10.0% v/v |
| Beta Estradiol | 0.07 mg/mL |
| Dove 0% alcohol anti-perspirant spraya | 0.19% w/v |
| Mucin (bovine) | 0.80% w/v |
| KY Jelly personal lubricant | 0.25% w/v |
| Leukocytes | 1x106 cells/mL |
| Monistat 1 | 0.25% w/v |
| Preparation H Hemorrhoidal Ointment | 0.25% w/v |
| Progesterone | 0.07 mg/mL |
| RepHresh Odor Eliminating pH Balancing Gelb | 1.25% w/v |
| Replens Long Lasting Vaginal Moisturizerc | 2.50% w/v |
| Seminal fluid | 5.00% v/v |
| Summer's Eve Povidone-Iodine Medicated Douche | 0.25% w/v |
| Summer's Eve, Cleansing Wash | 0.40% w/v |
| Vaginal anti-fungal | 0.25% w/v |
| 7-day Vaginal cream | 0.25% w/v |
| Vagisil Moisturizer | 0.25% w/v |
| Vagisil Regular Strength Anti-Itch Creme | 0.25% w/v |
| VCF Vaginal Contraceptive Gel | 0.25% w/v |
| Yeast Gard Douche Advanced | 0.25% w/v |
| Table 5. Potentially Interfering Substances | |||
|---|---|---|---|
| -- | -- | -- | --------------------------------------------- |
e 0% alcohol anti-perspirant spray may cause false positive results for CT. NG, and/or TV when present at a concentration greater than 0.19% (w/y epHresh Odor Eliminating pH Balancing Gel may cause false negative results for CT and/or NG when present at a concentration greater than 1.25% (w/) Replens Long Lasting Vaginal Moisturizer may cause invalid results when present at a concentration greater than 2.50% (w/y
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6. Reproducibility
A reproducibility study was performed to evaluate the reproducibility of the Visby Medical Sexual Health Click Test when used by untrained users in CLIA waived settings. The operators performing the testing were non-laboratorians representing healthcare professionals that may be encountered at such sites. The study evaluated four (4) panel members that were prepared using cultured organisms in negative clinical vaginal swab matrix. The study was performed with negative (unspiked) and positive samples. A total of six (6) study operators (2 operators at each site) tested the panel three (3) times each testing day, over six (6) nonconsecutive days. Three reagent lot were used in the study. A summary of the results (count correct / total count) and % agreement for each analysis is presented in the table below. The Visby Medical Sexual Health Click test demonstrated robust reproducibility with no significant effect observed for the components of variation evaluated (sites, days, operators, lots).
| Site 1 | Site 2 | Site 3 | Overall Agreement | ||
|---|---|---|---|---|---|
| Panel Member | % Agreement(count) | % Agreement(count) | % Agreement(count) | % Agreement(count) | 95% CI |
| CT Positive | 100% | 100% | 100% | 100% | 96.5%-100.0% |
| (49.72 EB/mL) | (35/35)a | (36/36)b | (36/36)c | (107/107) | |
| NG Positive | 97.1% | 94.3% | 100% | 97.2% | 92.0%-99.0% |
| (22.68 cfu/mL) | (34/35)a | (33/35)a | (36/36) | (103/106) | |
| TV Positive | 100% | 100% | 100% | 100% | 96.5%-100% |
| (21.6 troph/mL) | (36/36) | (35/35)a | (35/35)a | (106/106) | |
| Negative | 97.2%(35/36)d | 100%(36/36) | 97.2%(35/36)e | 98.1%(106/108) | 93.5%-99.5% |
| Table 6. Summary of Reproducibility Study Results | ||
|---|---|---|
| -- | --------------------------------------------------- | -- |
One sample had invalid results and was omitted from the analysis.
b One sample was CT positive, but unexpectedly positive for NG and T.
c Two samples were CT positive, but unexpected positive f
One sample was uuestedlynesitive for
One sample was unexpectedly positive for TV
e One sample was unexpectedly positive for NG
An additional study using low positive (spiked at ~1x LoD) and negative (unspiked) samples was performed to evaluate the repeatability of test results near the assay limit of detection when tested by untrained users in a CLIA waived setting. A total of six (6) operators (2 operators at each site) tested the panel twice a day for 5 days. The composition of the panel members along with summary of results (count correct / total count) and percent agreement with the expected result for each panel member is presented in the table below. The study demonstrated that untrained users can perform the test and interpret the results accurately when testing samples with organism concentrations near the LoD.
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| Site 1 | Site 2 | Site 3 | Overall Agreement | ||
|---|---|---|---|---|---|
| Panel Member | %Agreement(count) | %Agreement(count) | %Agreement(count) | %Agreement(count) | 95% CI |
| CT Low Positive(16.0 EB/mL) | 100%(20/20) | 100%(20/20) | 100%(20/20) | 100%(60/60) | 94.0%-100% |
| NG Low Positive(6.2 cfu/mL) | 95.0%(19/20) | 95.0%(19/20) | 100%(20/20) | 96.7%(58/60) | 88.6%-99.1% |
| TV Low Positive(1.2 troph/mL) | 100%(20/20) | 95.0%(19/20) | 95.0%(19/20) | 96.7%(58/60) | 88.6%-99.1% |
| Negative | 100%(18/18)* | 100%(20/20) | 100%(20/20) | 100%(58/58) | 93.8%-100% |
Table 7. Summary of Study with Sample Near Assay LoD
- Two samples had invalid results and were omitted from the analysis
7. External Control Lot-to-Lot Reproducibility
Lot-to-lot reproducibility of the external controls manufactured by ZeptoMetrix Corporation (Buffalo, NY) was evaluated. Three (3) unique lots of the single-use positive control and three (3) unique lots of the single-use negative control were evaluated on five Visby Medical Sexual Health Click tests each for a total of 30 tests. 100% concordance with expected results across all lots was observed.
During the analytic studies positive and negative controls were tested on each day that testing was performed. During the clinical study and reproducibility studies, a positive and negative control was tested for each new operator, for each new lot or shipment of reagents and every 30 days. A total of 490 external controls were tested during the analytic and clinical testing. Of these 459 (93.7%, 459/490) had an initial valid result. Of the 31 external controls that required a test, 29 had the correct valid result first retest and 2 required a 2nd retest to obtain a valid result.
8. Specimen Stability
Vaginal specimen stability was evaluated for specimens collected using the Visby Medical Sexual Health collection kit. Storage was evaluated at room temperature (15-30°C), refrigerated (2-8°C), and frozen (<-15°C) conditions. All three target organisms (CT, NG, and TV) were seeded into negative vaginal sample matrix at low (2x LoD), moderate (10x LoD), and high (1000x LoD) concentrations. For a timepoint to be considered acceptable, 95% concordance with expected results for low concentration samples and 100% concordance for moderate and high concentration samples were required.
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Based on the results of this study the claimed stability for vaginal specimens in the Visby Medical Sexual Health collection kit is 4 hours for room-temperature specimens, 4 hours for refrigerated specimens, and 90 days for frozen specimens.
H. Clinical Data
Performance characteristics of the Visby Sexual Health Click Test were established in two multi-center CLIA Waived studies conducted at 14 clinical sites. The sites were geographically distributed across the United States and included an OB/GYN physician's office, Sexual Health clinics, Primary Care clinics, a Public Health clinic, a university Student Health clinic, an HIV/AIDS clinic, and STD clinics. A total of 32 untrained operators, representative of CLIA waived users, participated in the study. The study subjects were prospectively enrolled females, 14 years of age and older, who selfcollected vaginal swab specimens using the Visby Vaginal Collection Kit. The average age among study participants was 34 years, with a range between 14 to 80 years of age.
The collected samples were provided to participating study operators who tested them on-site using the Visby Medical Sexual Health Click Test. The participating operators conducted the test by following the instructions in the Quick Reference Guide (QRG). The study operators had no formal training or experience with CLIA high or moderate complexity testing and did not receive any training on the use of the Visby test.
The Visby Sexual Health Click Test results were compared to a composite comparator result (CCR) for CT and NG and a patient infected status algorithm (PIS) for TV. The CCR and PIS was comprised of three FDA-cleared NAAT assays. A study participant was considered infected for CT, NG, or TV if a positive result was reported from two NAAT tests. If the test results of the first two NAAT were discordant, the CCR/PIS was determined by the third NAAT.
1899 subjects were initially enrolled, of which 1881 were eligible for inclusion. Of those, 1789 were included in the data analysis. The tables below summarize the clinical performance of the Visby Sexual Health Test.
| SymptomStatus | N | TP | FP | TN | FN | Prevalence% | PPA (95% CI) | NPA (95% CI) |
|---|---|---|---|---|---|---|---|---|
| Symptomatic | 918 | 95 | 26 | 795 | 2 | 10.6% | 97.9%(92.8-99.4%) | 96.8%(95.4-97.8%) |
| Asymptomatic | 856 | 54 | 10 | 790 | 2 | 6.5% | 96.4%(87.9-99.0%) | 98.8%(97.7-99.3%) |
| Overall | 1774 | 149 | 36 | 1585 | 4 | 8.6% | 97.4%(93.5-99.0%) | 97.8%(96.9-98.4%) |
Table 8. Clinical Performance of the Visby Test for CT vs. Composite Comparator Results
PPA=Positive Percent agreement with CCR; NPA=Negative Percent Agreement with CCR; TP=true positive; FP=false positive; TN=true negative; FN=false negative
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| SymptomStatus | N | TP | FP | TN | FN | Prevalence% | PPA (95% CI) | NPA (95% CI) |
|---|---|---|---|---|---|---|---|---|
| Symptomatic | 929 | 25 | 8 | 896 | 0 | 2.7% | 100.0%(86.7-100.0%) | 99.1%(98.3-99.6%) |
| Asymptomatic | 857 | 19 | 8 | 829 | 1 | 2.3% | 95.0%(76.4-99.1%) | 99.0%(98.1-99.5%) |
| Overall | 1786 | 44 | 16 | 1725 | 1 | 2.5% | 97.8%(88.4-99.6%) | 99.1%(98.5-99.4%) |
Table 9. Clinical Performance of the Visby Test for NG vs. Composite Comparator Results
PPA=Positive Percent agreement with CRA; NPA=Negative Percent Agreement with CRA; TP=true positive; FP=false positive; TN=true negative; FN=false negative
Table 10. Clinical Performance of the Visby Test for TV vs. PIS
| SymptomStatus | N | TP | FP | TN | FN | Prevalence% | Sensitivity %(95% CI) | Specificity %(95% CI) |
|---|---|---|---|---|---|---|---|---|
| Symptomatic | 916 | 83 | 35 | 797 | 1 | 9.2% | 98.8%(93.6%-99.8%) | 95.8%(94.2%-97.0%) |
| Asymptomatic | 849 | 53 | 18 | 778 | 0 | 6.2% | 100%(93.2%-100.0%) | 97.7%(96.5%-98.6%) |
| Overall | 1765 | 136 | 53 | 1575 | 1 | 7.8% | 99.3%(96.0%-99.9%) | 96.7%(95.8%-97.5%) |
TP=true positive; FP=false positive; TN=true negative; FN=false negative
CLIA Waiver Considerations 1.
A CLIA waiver application was also submitted for the Visby Medical Sexual Health Click test. Comprehensive flex testing was performed to evaluate the robustness of the test when subjected to a variety of environmental stresses and operational error. The results of these studies have demonstrated that the test gave the expect result or invalid results when subjected to operational errors (e.g., incorrect order of operation, reading results after the 2-hour read window, adding the incorrect sample type or sample volume, testing samples outside of the established specimen stability limits, incorrect device positioning) or exposure environmental conditions that are outside of the operating specifications (e.g., temperature, humidity, vibration, lighting, device positioning and agitation. There were no instances of erroneous test results in these studies.
§ 866.3393 Device to detect nucleic acids from non-viral microorganism(s) causing sexually transmitted infections and associated resistance marker(s).
(a)
Identification. A device to detect nucleic acids from non-viral microorganism(s) causing sexually transmitted infections and associated resistance marker(s) is an in vitro diagnostic device intended for the detection and identification of nucleic acids from non-viral microorganism(s) and their associated resistance markers in clinical specimens collected from patients suspected of sexually transmitted infections. The device is intended to aid in the diagnosis of non-viral sexually transmitted infections in conjunction with other clinical and laboratory data. These devices do not provide confirmation of antibiotic susceptibility since mechanisms of resistance may exist that are not detected by the device.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The intended use for the labeling required under § 809.10 of this chapter must include a detailed description of targets the device detects, the results provided to the user, the clinical indications appropriate for test use, and the specific population(s) for which the device is intended.
(2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device; alternatively, the sample collection device must be cleared in a premarket submission as a part of this device.
(3) The labeling required under § 809.10(b) of this chapter must include:
(i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens;
(ii) Detailed discussion of the performance characteristics of the device for all claimed specimen types based on analytical studies, including Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, within lab precision, and reproducibility, as appropriate;
(iii) Detailed descriptions of the test procedure, the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing;
(iv) Limiting statements indicating that:
(A) A negative test result does not preclude the possibility of infection;
(B) The test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician;
(C) Reliable results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe proper procedures in any one of these steps can lead to incorrect results; and
(D) If appropriate (
e.g., recommended by the Centers for Disease Control and Prevention, by current well-accepted clinical guidelines, or by published peer reviewed research), that the clinical performance is inferior in a specific clinical subpopulation or for a specific claimed specimen type; and(v) If the device is intended to detect antimicrobial resistance markers, limiting statements, as appropriate, indicating that:
(A) Negative results for claimed resistance markers do not indicate susceptibility of detected microorganisms, as resistance markers not measured by the assay or other potential mechanisms of antibiotic resistance may be present;
(B) Detection of resistance markers cannot be definitively linked to specific microorganisms and the source of a detected resistance marker may be an organism not detected by the assay, including colonizing flora;
(C) Detection of antibiotic resistance markers may not correlate with phenotypic gene expression; and
(D) Therapeutic failure or success cannot be determined based on the assay results, since nucleic acid may persist following appropriate antimicrobial therapy.
(4) Design verification and validation must include:
(i) Detailed device description documentation, including methodology from obtaining sample to result, design of primer/probe sequences, rationale for target sequence selection, and computational path from collected raw data to reported result (
e.g., how collected raw signals are converted into a reported result).(ii) Detailed documentation of analytical studies, including, Limit of Detection, inclusivity, cross-reactivity, microbial interference, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, within lab precision, and reproducibility, as appropriate.
(iii) Detailed documentation and performance results from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, when determined to be appropriate by FDA, additional characterized clinical samples. The study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained from FDA accepted comparator methods. Documentation from the clinical studies must include the clinical study protocol (including a predefined statistical analysis plan) study report, testing results, and results of all statistical analyses.
(iv) A detailed description of the impact of any software, including software applications and hardware-based devices that incorporate software, on the device's functions.