(77 days)
The Cepheid Xpert TV Assay, performed on the GeneXpert® Instrument Systems, is a qualitative in vitro diagnostic test for the detection of Trichomonas vaginalis genomic DNA. The test utilizes automated real-time polymerase chain reaction (PCR) to detect Trichomonas vaginalis genomic DNA. The Xpert TV Assay uses female and male urine specimens, endocervical swab specimens, and patient-collected vaginal swab specimens (collected in a clinical setting). The Xpert TV Assay is intended to aid in the diagnosis of trichomoniasis in symptomatic or asymptomatic individuals.
Ancillary Collection Kits:
Xpert Vaginal/Endocervical Specimen Collection Kit
The Cepheid® Xpert® Vaginal/Endocervical Specimen Collection Kit is designed to collect, preserve, and transport Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis DNA in endocervical swab specimens (collected by a clinician) and patient-collected vaginal swab specimens (collected in a clinical setting) from symptomatic and asymptomatic women prior to analysis with the Xpert CT/NG Assay and the Xpert TV Assay.
Xpert Urine Specimen Collection Kit
The Cepheid® Xpert® Urine Specimen Collection Kit is designed to preserve and transport Chlamydia trachomatis. Neisseria gonorrhoeae, and Trichomonas vaginalis DNA in first-catch female urine specimens from symptomatic and asymptomatic individuals prior to analysis with the Xpert CT/NG Assay and the Xpert TV Assay.
The Xpert TV Assay is an automated real-time polymerase chain reaction (PCR) in vitro diagnostic test for qualitative detection of genomic DNA from Trichomonas vaginalis. The Xpert TV Assay is intended as an aid in the diagnosis of trichomoniasis.
The Xpert TV Assay is performed on the Cepheid GeneXpert® Instrument Systems (GeneXpert Dx., GeneXpert Infinity-48, GeneXpert Infinity-48s, and GeneXpert Infinity-80 systems). The GeneXpert Instrument System platform automates sample preparation, amplification and real-time detection.
The GeneXpert Instrument Systems require the use of single-use, disposable cartridges (the Xpert TV cartridges) that hold the PCR reagents and host the PCR process. Because the cartridges are self-contained and specimens never come into contact with working parts of the instrument modules, cross-contamination between samples is minimized.
The Xpert TV Assay cartridges contain reagents for the detection of genomic DNA from T. vaginalis for use with the following specimens collected from symptomatic and asymptomatic individuals: female and male urine, endocervical swab and patientcollected vaginal swab (collected in a clinical setting). A Sample Processing Control (SPC), Sample Adequacy Control (SAC), and a Probe Check Control (PCC) are controls utilized by the GeneXpert Instrument System platform. The SPC, SAC, and PCC are controls utilized by the GeneXpert Instrument System platform. The SPC is present to control for adequate processing of the target trichomonads and to monitor the presence of inhibitors in the real-time PCR reaction to reduce the possibility of false negative results. The SAC reagents detect the presence of a single copy human gene and monitor whether the specimen contains human cells. The PCC verifies reagent rehydration, real-time PCR tube filling in the cartridge, probe integrity, and dye stability.
The single-use, multi-chambered fluidic cartridges are designed to complete sample preparation and real-time PCR for the detection of genomic DNA from T. vaginalis in 70 minutes or less. The GeneXpert Instrument Systems, comprised of the GeneXpert Dx Systems and the GeneXpert Infinity Systems, have 1 to 80 randomly accessible modules, depending upon the instrument, that are each capable of performing separate sample preparation and real-time PCR and RT-PCR tests. Each module contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores', and a proprietary I-CORE® thermocycler for performing real-time PCR and RT-PCR and detection.
The swab and/or urine specimens are collected from asymptomatic or symptomatic patients and placed into a specimen transport tube containing preservative. The specimen is transferred to the sample chamber of the disposable fluidic cartridge (the Xpert TV cartridge). The user initiates a test from the system user interface and places the cartridge into the GeneXpert instrument platform, which performs hands-off real-time, multiplex PCR for detection of DNA. The results are automatically generated at the end of the process in a report that can be viewed and printed.
The ancillary specimen collection kits for use with the Xpert TV Assay are the Cepheid Xpert Vaginal/Endocervical Specimen Collection Kit and the Cepheid Xpert Urine Specimen Collection Kit.
This document describes the Xpert TV Assay, a qualitative in vitro diagnostic test for the detection of Trichomonas vaginalis genomic DNA, performed on GeneXpert Instrument Systems.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated as numerical targets in a dedicated table. However, the study aims to demonstrate "substantial equivalence" to a predicate device (Cepheid Xpert TV Assay [510(k) #K151565]) based on analytical and clinical performance. The reported performance suggests the device aims for high sensitivity and specificity in detecting T. vaginalis.
The following table summarizes the key performance metrics reported from the clinical study:
| Metric | Specimen Type (Symptomatic Status) | Reported Performance (95% CI) |
|---|---|---|
| Sensitivity | Endocervical Swabs (Symptomatic) | 100% (94.9%-100%) |
| Endocervical Swabs (Asymptomatic) | 98.1% (93.4%-99.8%) | |
| Endocervical Swabs (Overall) | 98.9% (96.0%-99.9%) | |
| Patient-Collected Vaginal Swabs (Symptomatic) | 98.6% (92.7%-100%) | |
| Patient-Collected Vaginal Swabs (Asymptomatic) | 95.0% (89.3%-98.1%) | |
| Patient-Collected Vaginal Swabs (Overall) | 96.4% (92.7%-98.5%) | |
| Female Urine (Symptomatic) | 98.6% (92.5%-100%) | |
| Female Urine (Asymptomatic) | 98.2% (93.6%-99.8%) | |
| Female Urine (Overall) | 98.4% (95.3%-99.7%) | |
| Male Urine (Symptomatic) | 87.5% (71.9%-95.0%) | |
| Male Urine (Asymptomatic) | 90.3% (82.6%-94.8%) | |
| Male Urine (Overall) | 89.6% (83.0%-93.8%) | |
| Specificity | Endocervical Swabs (Symptomatic) | 98.5% (97.2%-99.3%) |
| Endocervical Swabs (Asymptomatic) | 99.1% (98.3%-99.6%) | |
| Endocervical Swabs (Overall) | 98.9% (98.3%-99.3%) | |
| Patient-Collected Vaginal Swabs (Symptomatic) | 99.5% (98.6%-99.9%) | |
| Patient-Collected Vaginal Swabs (Asymptomatic) | 99.6% (99.0%-99.9%) | |
| Patient-Collected Vaginal Swabs (Overall) | 99.6% (99.1%-99.8%) | |
| Female Urine (Symptomatic) | 99.8% (99.1%-100%) | |
| Female Urine (Asymptomatic) | 99.6% (99.0%-99.9%) | |
| Female Urine (Overall) | 99.7% (99.3%-99.9%) | |
| Male Urine (Symptomatic) | 99.8% (99.3%-99.9%) | |
| Male Urine (Asymptomatic) | 99.2% (98.8%-99.4%) | |
| Male Urine (Overall) | 99.3% (99.0%-99.5%) | |
| Reproducibility (Agreement with Expected Results) | FS-Neg (Female Swab Negative) | 100% (144/144) (Across 3 sites) |
| FS-Mod Pos (Female Swab Moderate Positive) | 100% (144/144) (Across 3 sites) | |
| FS-LoD (Female Swab LoD) | 95.8% (138/144) (Across 3 sites) | |
| FS-High Neg (Female Swab High Negative) | 76.4% (110/144) (Across 3 sites) | |
| UR-Neg (Urine Negative) | 100% (144/144) (Across 3 sites) | |
| UR-Mod Pos (Urine Moderate Positive) | 100% (144/144) (Across 3 sites) | |
| UR-LoD (Urine LoD) | 88.8% (127/143) (Across 3 sites) | |
| UR-High Neg (Urine High Negative) | 70.8% (102/144) (Across 3 sites) | |
| Precision (Agreement with Expected Results) | FS-Neg (Female Swab Negative) | 99.7% (287/288) (Across 3 instruments) |
| FS-Mod Pos (Female Swab Moderate Positive) | 100% (288/288) (Across 3 instruments) | |
| FS-LoD (Female Swab LoD) | 91.7% (264/288) (Across 3 instruments) | |
| FS-High Neg (Female Swab High Negative) | 75.6% (217/287) (Across 3 instruments) | |
| UR-Neg (Urine Negative) | 100% (287/287) (Across 3 instruments) | |
| UR-Mod Pos (Urine Moderate Positive) | 100% (288/288) (Across 3 instruments) | |
| UR-LoD (Urine LoD) | 94.1% (271/288) (Across 3 instruments) | |
| UR-High Neg (Urine High Negative) | 77.8% (224/288) (Across 3 instruments) |
2. Sample Size for Test Set and Data Provenance
- Test Set (Clinical Performance):
- Female Study Participants: 1867 unique individuals. However, the tables break down results by specimen type and symptomatic status, showing total N for each subgroup. For example, Endocervical Swabs (Overall) had 1799 samples, Patient-Collected Vaginal Swabs (Overall) had 1791 samples, and Female Urine (Overall) had 1793 samples. It's implied these are from the 1867 female participants.
- Male Study Participants: 4626 unique individuals, with 4611 urine samples tested (Overall).
- Total Tests Performed: 10,017 (including initial invalid results).
- Data Provenance: Prospective, multi-site investigational study with samples collected from 17 clinical sites in the US.
3. Number of Experts and Qualifications for Ground Truth
The document does not explicitly mention "experts" establishing ground truth in the traditional sense of multiple individual reviewers. Instead, the ground truth (Patient Infected Status - PIS) was established algorithmically based on reference laboratory tests:
- For female specimen types: Culture and a validated FDA-cleared NAAT test.
- For male urine: Culture and validated bidirectional sequencing (primary sequencing).
The qualifications of personnel performing these reference tests are not specified but would typically be laboratory professionals trained in these methods.
4. Adjudication Method for the Test Set
The adjudication method was a "patient infected status (PIS) algorithm" defined as follows:
- A study participant was considered infected by PIS if any one of the two reference test results (culture or NAAT/sequencing) were positive.
- The subject was considered not infected by PIS when both reference test results were negative.
For discrepant results between the Xpert TV Assay and the PIS, validated bi-directional Sanger sequencing was performed, but these results were "footnoted for informational purposes only" and did not change the primary PIS definition.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study was done. This study focuses on the performance of the device itself (standalone) against a composite reference standard (PIS), not on how human readers' performance might improve with or without AI assistance from this device. The device is an automated in vitro diagnostic test, not an AI-assisted diagnostic aid for human interpretation.
6. Standalone Performance
Yes, a standalone performance study was done. The entire clinical performance section evaluates the Xpert TV Assay's performance (sensitivity, specificity, PPV, NPV) directly against the Patient Infected Status (PIS) algorithm without human interpretation of the device's output. The device itself produces a "TV DETECTED" or "TV NOT DETECTED" result.
7. Type of Ground Truth Used
The ground truth used was a composite reference standard termed "Patient Infected Status (PIS) algorithm." This PIS was established from a combination of:
- Culture
- Validated bidirectional sequencing (for male urine)
- FDA-cleared NAAT test (for female specimens)
8. Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of machine learning or AI development. Since this is an in vitro diagnostic device for nucleic acid detection (real-time PCR), it typically relies on pre-defined primer/probe sets and reaction conditions rather than a machine learning model that requires a distinct training set. The assay's development would involve analytical studies (e.g., LoD, inclusivity, specificity) using spiked samples and isolates, but these are not referred to as a "training set" in the common AI sense.
9. How the Ground Truth for the Training Set Was Established
As noted above, a "training set" in the AI sense is not applicable here. The analytical studies (LoD, inclusivity, specificity) used well-characterized Trichomonas vaginalis strains (e.g., ATCC® 30001™, ATCC® 30238™) and other microorganisms at specific concentrations, often spiked into negative clinical matrices. The ground truth for these analytical studies was established by:
- Known concentrations of characterized organisms for LoD and inclusivity.
- Known presence or absence of specific microorganisms at specified concentrations for analytical specificity/cross-reactivity and competitive interference.
- Visual enumeration by light microscopy for T. vaginalis cell counts.
- CFU/mL, genomes/mL, or TCID50/mL for other microorganisms.
{0}------------------------------------------------
Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing right, resembling a bird in flight.
August 29, 2016
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
Cepheid Scott Campbell, Ph.D., MBA Corporate Vice President and Chief Regulatory Officer 904 Caribbean Drive Sunnyvale, CA 94089-1189
Re: K161619
Trade/Device Name: Xpert® TV, Cepheid GeneXpert® Instrument Systems (GeneXpert Dx, GeneXpert Infinity-48, GeneXpert Infinity-48s, and GeneXpertInfinity-80 systems). Xpert® Vaginal/Endocervical Specimen Collection Kit and Xpert® Urine Specimen Collection Kit. Regulation Number: 21 CFR 866.3860 Regulation Name: Trichomonas vaginalis nucleic acid assay
Regulatory Class: II Product Code: OUY, OOI, JSM Dated: June 10, 2016 Received: June 15, 2016
Dear Dr. Campbell:
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. 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.
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 Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements
{1}------------------------------------------------
as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. 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
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Steven R. Gitterman -S
for Uwe Scherf, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
{2}------------------------------------------------
Indications for Use
510(k) Number (if known) K161619
Device Name Xpert® TV
Indications for Use (Describe)
The Cepheid Xpert TV Assay, performed on the GeneXpert® Instrument Systems, is a qualitative in vitro diagnostic test for the detection of Trichomonas vaginalis genomic DNA. The test utilizes automated real-time polymerase chain reaction (PCR) to detect Trichomonas vaginalis genomic DNA. The Xpert TV Assay uses female and male urine specimens, endocervical swab specimens, and patient-collected vaginal swab specimens (collected in a clinical setting). The Xpert TV Assay is intended to aid in the diagnosis of trichomoniasis in symptomatic or asymptomatic individuals.
Ancillary Collection Kits:
Xpert Vaginal/Endocervical Specimen Collection Kit
The Cepheid® Xpert® Vaginal/Endocervical Specimen Collection Kit is designed to collect, preserve, and transport Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis DNA in endocervical swab specimens (collected by a clinician) and patient-collected vaginal swab specimens (collected in a clinical setting) from symptomatic and asymptomatic women prior to analysis with the Xpert CT/NG Assay and the Xpert TV Assay.
Xpert Urine Specimen Collection Kit
The Cepheid® Xpert® Urine Specimen Collection Kit is designed to preserve and transport Chlamydia trachomatis. Neisseria gonorrhoeae, and Trichomonas vaginalis DNA in first-catch female urine specimens from symptomatic and asymptomatic individuals prior to analysis with the Xpert CT/NG Assay and the Xpert TV Assay.
| 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) |
CONTINUE ON A SEPARATE PAGE IF NEEDED.
This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.
The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff(@fda.hhs.gov
"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."
{3}------------------------------------------------
510(k) Summary
As required by 21 CFR Section 807.92(c).
| Submitted by: | Cepheid904 Caribbean DriveSunnyvale, CA 90489Phone number: (847) 228-3299Fax number: (847) 593-0233 |
|---|---|
| Contact: | Scott A. Campbell, PhD, MBA |
| Date of Preparation: | July 13, 2016 |
| Device: | |
| Trade name: | Xpert® TV |
| Common name: | Xpert TV Assay |
| Type of Test: | Real-Time Polymerase Chain Reaction (PCR) for the detectionof Trichomonas vaginalis |
| Regulation number/Classification name/ | 866.3860/ Trichomonas vaginalis nucleic acid amplification testsystem /OUY |
| Product code: | 862.2570/Instrumentation for clinical multiplex testsystems/OOI |
| ClassificationAdvisory Panel | Microbiology (83) |
| Prescription Use | Yes |
| Predicate DeviceAssay: | Cepheid Xpert TV Assay[510(k) #K151565] |
| Predicate DeviceAssay: | Xpert Urine Specimen Collection Kit[510(k) #K151565] |
{4}------------------------------------------------
Device Description:
The Xpert TV Assay is an automated real-time polymerase chain reaction (PCR) in vitro diagnostic test for qualitative detection of genomic DNA from Trichomonas vaginalis. The Xpert TV Assay is intended as an aid in the diagnosis of trichomoniasis.
The Xpert TV Assay is performed on the Cepheid GeneXpert® Instrument Systems (GeneXpert Dx., GeneXpert Infinity-48, GeneXpert Infinity-48s, and GeneXpert Infinity-80 systems). The GeneXpert Instrument System platform automates sample preparation, amplification and real-time detection.
The GeneXpert Instrument Systems require the use of single-use, disposable cartridges (the Xpert TV cartridges) that hold the PCR reagents and host the PCR process. Because the cartridges are self-contained and specimens never come into contact with working parts of the instrument modules, cross-contamination between samples is minimized.
The Xpert TV Assay cartridges contain reagents for the detection of genomic DNA from T. vaginalis for use with the following specimens collected from symptomatic and asymptomatic individuals: female and male urine, endocervical swab and patientcollected vaginal swab (collected in a clinical setting). A Sample Processing Control (SPC), Sample Adequacy Control (SAC), and a Probe Check Control (PCC) are controls utilized by the GeneXpert Instrument System platform. The SPC, SAC, and PCC are controls utilized by the GeneXpert Instrument System platform. The SPC is present to control for adequate processing of the target trichomonads and to monitor the presence of inhibitors in the real-time PCR reaction to reduce the possibility of false negative results. The SAC reagents detect the presence of a single copy human gene and monitor whether the specimen contains human cells. The PCC verifies reagent rehydration, real-time PCR tube filling in the cartridge, probe integrity, and dye stability.
The single-use, multi-chambered fluidic cartridges are designed to complete sample preparation and real-time PCR for the detection of genomic DNA from T. vaginalis in 70 minutes or less. The GeneXpert Instrument Systems, comprised of the GeneXpert Dx Systems and the GeneXpert Infinity Systems, have 1 to 80 randomly accessible modules, depending upon the instrument, that are each capable of performing separate sample preparation and real-time PCR and RT-PCR tests. Each module contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores', and a proprietary I-CORE® thermocycler for performing real-time PCR and RT-PCR and detection.
The swab and/or urine specimens are collected from asymptomatic or symptomatic patients and placed into a specimen transport tube containing preservative. The specimen is transferred to the sample chamber of the disposable fluidic cartridge (the Xpert TV cartridge). The user initiates a test from the system user interface and places the cartridge
1 Although sonication is a fundamental capability of every GeneXpert module, sonication is not used in the Xpert TV Assay.
{5}------------------------------------------------
into the GeneXpert instrument platform, which performs hands-off real-time, multiplex PCR for detection of DNA. The results are automatically generated at the end of the process in a report that can be viewed and printed.
The ancillary specimen collection kits for use with the Xpert TV Assay are the Cepheid Xpert Vaginal/Endocervical Specimen Collection Kit and the Cepheid Xpert Urine Specimen Collection Kit.
Device Intended Use:
The Cepheid Xpert TV Assay, performed on the GeneXpert Instrument Systems, is a qualitative in vitro diagnostic test for the detection of Trichomonas vaginalis genomic DNA. The test utilizes automated real-time polymerase chain reaction (PCR) to detect Trichomonas vaginalis genomic DNA. The Xpert TV Assay uses female and male urine specimens, endocervical swab specimens, and patient-collected vaginal swab specimens (collected in a clinical setting). The Xpert TV Assay is intended to aid in the diagnosis of trichomoniasis in symptomatic or asymptomatic individuals.
Ancillary Collection Kits:
Xpert Vaginal/Endocervical Specimen Collection Kit
The Cepheid® Xpert® Vaginal/Endocervical Specimen Collection Kit is designed to collect, preserve, and transport Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis DNA in endocervical swab specimens (collected by a clinician) and patient-collected vaginal swab specimens (collected in a clinical setting) from symptomatic and asymptomatic women prior to analysis with the Xpert CT/NG Assay and the Xpert TV Assay.
Xpert Urine Specimen Collection Kit
The Cepheid® Xpert® Urine Specimen Collection Kit is designed to preserve and transport Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis DNA in first-catch female and male urine specimens from symptomatic and asymptomatic individuals prior to analysis with the Xpert CT/NG Assay and the Xpert TV Assay.
Substantial Equivalence:
The Xpert TV Assay is substantially equivalent to the cleared Cepheid Xpert TV Assay [510(k) #K151565]. The assays are identical in reagents and formulation and use the same real-time PCR technology and GeneXpert instruments. The performance of the Xpert TV Assay was evaluated in a multi-site clinical study in which the performance of the Xpert TV Assay was compared to a patient-infected status (PIS). The results of the study demonstrated that the performance of the Xpert TV Assay is substantially equivalent to the predicate device.
{6}------------------------------------------------
Table 5-1 shows the similarities and differences between the Xpert TV Assay and the predicate device.
| Similarities | ||
|---|---|---|
| Item | Device | Predicate Device |
| Cepheid Xpert TV Assay | Current CepheidXpert TV Assay | |
| 510(k) Number | K161619 | K151565 |
| Regulation | Same | 866.3860 |
| Product Code | Same | OUY |
| Device Class | Same | II |
| Intended Use | The Cepheid Xpert TV Assay,performed on the GeneXpert®Instrument Systems, is aqualitative in vitro diagnostictest for the detection ofTrichomonas vaginalisgenomic DNA. The testutilizes automated real-timepolymerase chain reaction(PCR) to detect Trichomonasvaginalis genomic DNA. TheXpert TV Assay uses femaleand male urine specimens,endocervical swab specimens,or patient-collected vaginalswab specimens (collected in aclinical setting). The XpertTV Assay is intended to aid inthe diagnosis of trichomoniasisin symptomatic orasymptomatic individuals. | The Cepheid Xpert TV Assay,performed on the GeneXpert®Instrument Systems, is aqualitative in vitro diagnostictest for the detection ofTrichomonas vaginalisgenomic DNA. The testutilizes automated real-timepolymerase chain reaction(PCR) to detect Trichomonasvaginalis genomic DNA. TheXpert TV Assay uses femaleurine specimens, endocervicalswab specimens, or patient-collected vaginal swabspecimens (collected in aclinical setting). The XpertTV Assay is intended to aid inthe diagnosis of trichomoniasisin symptomatic orasymptomatic individuals. |
| Assay Targets | Same | T. vaginalis genomic DNA |
| Specimen Types | Endocervical SwabsVaginal SwabsFemale UrineMale Urine | Endocervical SwabsVaginal SwabsFemale Urine |
| Table 5-1: Comparison of Similarities and Differences of the |
|---|
| Xpert TV Assay with the Predicate Device |
{7}------------------------------------------------
| Similarities | ||
|---|---|---|
| Item | Device | Predicate Device |
| Cepheid Xpert TV Assay | Current CepheidXpert TV Assay | |
| Nucleic AcidExtraction | Yes | Yes |
| Assay Results | Same | Qualitative |
| Collection Kit | Same | Urine collection kitSwab collection kit |
| Technology/Detection | Same | Real-time polymerase chainreaction (PCR) |
| Instrument System | Same | Cepheid GeneXpertInstrument System |
| Laboratory Users | Same | Operators in Moderate andHigh Complexity labs |
| Early assaytermination function | Same | Yes(for positive samples) |
| Primary Differences | ||
|---|---|---|
| New Device | Predicate Device | |
| Item | Cepheid Xpert TV Assay | Current CepheidXpert TV Assay |
| Specimen Types | Endocervical SwabsVaginal SwabsFemale UrineMale Urine | Endocervical SwabsVaginal SwabsFemale Urine |
The Xpert TV Assay has the same general intended use as the predicate device and has the same technological characteristics as the predicate device. The differences between the Xpert TV Assay and the predicate device do not raise different questions of safety and effectiveness. The clinical study demonstrates that the Xpert TV Assay is acceptable for its intended use with inexperienced lab users and is substantially equivalent to the predicate device described above.
{8}------------------------------------------------
Ancillary Collection Kit:
Xpert Urine Specimen Collection Kit
The predicate device for the Cepheid Xpert Urine Specimen Collection Kit is the current Cepheid Xpert Urine Specimen Collection Kit [510(k) # K151565]. The similarities and differences are shown in Table 5-2.
| Similarities | ||
|---|---|---|
| Item | DeviceCepheid Xpert UrineSpecimen Collection Kit | PredicateCurrent Cepheid Xpert UrineSpecimen Collection Kit |
| Intended Use(Similarities) | The collection kit is designedto preserve and transportChlamydia trachomatis ,Neisseria gonorrhoeae andTrichomonas vaginalis DNA infirst-catch male and femaleurine specimens fromsymptomatic andasymptomatic individuals priorto analysis. | The collection kit is designedto preserve and transportChlamydia trachomatis andNeisseria gonorrhoeae andTrichomonas vaginalis DNA infirst-catch female urinespecimens from symptomaticand asymptomatic individualsprior to analysis. |
| Single-use Device | Yes | Yes |
| Transport MediumpH | Same | 7.95 – 8.35 |
| Description | Same | Contains one individuallypackaged sterile disposabletransfer pipette and one urinetransport reagent tube.Approximately 7 mL of a first-catch urine specimen istransferred to the UrineTransport Reagent tube topreserve and transport thespecimen prior to analysis withthe assay. |
Table 5-2: Comparison of Similarities and Differences of the Xpert Urine Specimen Collection Kit with the Predicate Device
{9}------------------------------------------------
| Differences | ||
|---|---|---|
| Device | Predicate | |
| Item | Cepheid Xpert UrineSpecimen Collection Kit | Current Cepheid Xpert UrineSpecimen Collection Kit |
| Intended Use(differences) | Specimen storage and transportwhen testing for the presence ofChlamydia trachomatis andNeisseria gonorrhoeae in first-catch male and female urinespecimens and for the presenceof Trichomonas vaginalis infirst-catch female and maleurine specimens. | Specimen storage and transportwhen testing for the presence ofChlamydia trachomatis andNeisseria gonorrhoeae in first-catch male and female urinespecimens and for the presenceof Trichomonas vaginalis infirst-catch female urinespecimens. |
Non-Clinical Studies:
Analytical Sensitivity (Limit of Detection)
The analytical sensitivity or limit of detection (LoD) of the Xpert TV Assay was assessed using two Trichomonas vaginalis strains, one metronidazole susceptible (T. vaginalis ATCC® 30001™), and one metronidazole resistant (T. vaginalis ATCC® 30238"). The strains were tested individually in clinical T. vaginalis-negative pooled urine matrix in Cepheid Xpert Urine Transport Reagent and clinical T. vaginalisnegative pooled vaginal swab matrix (VS) in Cepheid Xpert Swab Transport Reagent.
T. vaginalis was cultured and incubated at 35°C. Visual examination of the cultures for white precipitate (indicating growth) was conducted every 24 hours for 3 to 5 days. Cell pellets were resuspended in growth medium and enumerated visually using light microscopy. The concentration of isolates was expressed as the number of cells per milliliter (cells/mL). Cultures were diluted in culture medium to 1 x10+ cells/mL and stored at -20°C. Cells were thawed on ice for use in the study.
The LoD was estimated by testing replicates of 20 at five concentrations for each strain and sample type over three days. The LoD for each strain was estimated by probit analysis. The claimed LoDs were confirmed by analyzing at least 20 replicates with T. vaginalis cells diluted to the estimated LoD concentrations. The LoD is defined as the lowest number of cells/mL that can be reproducibly distinguished from negative samples with 95% confidence or the lowest concentration at which 19 of 20 replicates were positive. The study was performed with two different lots of Xpert TV reagents and the claimed LoD for each strain is the higher of the two determinations (Table 5-3). The claimed LoD for T. vaginalis strains ATCC 30001 and ATCC 30238 in vaginal swab matrix is 2 cells/mL. The claimed LoD for T. vaginalis strain ATCC 30001 in urine matrix is 3 cells/mL. The claimed LoD for T. vaginalis strain ATCC 30238 in
{10}------------------------------------------------
urine matrix is 2 cells/mL.
The LoD point estimates and confirmed LoD for each strain tested are summarized in Table 5-3.
| Trichomonasvaginalis | LoD Estimates byProbit Analysis(cells/mL) | VerifiedLoD(cells/mL) | Verification(Positives/20) | Mean TVCt | Mean SACCt | Mean SPCCt | LoDClaim(cells/mL) | |
|---|---|---|---|---|---|---|---|---|
| strain and matrix | ReagentLot 1 | ReagentLot 2 | ||||||
| ATCC 30001 inVaginal Swab | 2.0 | 1.6 | 2.0 | 20/20 | 39.1 | 21.4 | 33.9 | 2 |
| ATCC 30238 inVaginal Swab | 1.7 | 2.1 | 2.1 | 20/20 | 37.5 | 21.4 | 33.7 | 2 |
| ATCC 30001 inUrine | 2.2 | 2.5 | 2.5 | 20/20 | 38.2 | 29.3 | 34.1 | 3 |
| ATCC 30238 inUrine | 2.1 | 1.7 | 2.1 | 20/20 | 38.2 | 29.2 | 33.8 | 2 |
Table 5-3: LoD of Two T. vaginalis Strains in Pooled Vaginal Swab Matrix and Urine Matrix
Analytical Specificity (Cross-reactivity and Competitive Interference)
A panel of 124 microorganisms, including bacteria, fungi, and viruses commonly found in the urogenital tract, as well as other protozoans closely related to T. vaginalis were tested with the Xpert TV Assay. The microorganisms were tested in the presence (competitive interference) and absence (cross-reactivity) of 3X LoD T. vaginalis ATCC 30001 cells. The microorganisms were seeded into either pooled Trichomonas vaginalis-negative urine matrix (patient urine added to Cepheid Urine Transport Reagent) or pooled Trichomonas vaginalis-negative vaginal swab matrix (vaginal swabs collected into Cepheid Swab Transport Reagent).
Each bacterial or fungal strain was tested at 1 x 10°CFU/mL or greater or at 1 x 10° genomes/mL. Viral strains were tested at 1 x 105 TCIDs0/mL or 105 genomes/mL or greater. Protozoans were cultured in growth media, visually enumerated by light microscopy and tested at 1 x 105 cells/mL or greater or 105 genomes/mL. All microorganisms were tested in triplicate. Positive and negative controls were included in the study. One organism, Trichomonas tenax, demonstrated cross-reactivity (result of TV DETECTED in the absence of TV) at 1 x 10 cells/mL for the urine and vaginal swab matrix samples. Trichomonas tenax was subjected to repeat analysis at various other concentrations until a result of TV NOT DETECTED was obtained (at 1 x 10- cells/mL). This is addressed in Limitations in the package insert. For the other 123 microorganisms. all TV positive samples remained positive and all TV negative samples remained negative, indicating that there was no interference or cross-reactivity with the results of the Xpert TV Assay for these microorganisms. Results are shown in Table 5-4 and Table 5-5 for urine and vaginal swab matrix, respectively.
{11}------------------------------------------------
| Microorganism | ConcentrationTesteda | Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | |
|---|---|---|---|---|
| Achromobacter xerosis | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Acinetobacter calcoaceticus | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Acinetobacter lwoffii | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Actinomyces israeliib | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Actinomyces pyogenes | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Aerococcus viridans | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Aeromonas hydrophila | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Alcaligenes faecalis | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Atopobium vaginaeb | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Bacillus subtilis | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Bacteroides fragilisb | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Bacteroides ureolyticusb | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Bifidobacterium adolescentisb | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Bifidobacterium brevi (breve)b | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Blastocystis hominisc | 1 x 105d | TV NOT DETECTED | TV DETECTED | |
| Branhamella catarrhalis | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Brevibacterium linens | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Campylobacter jejuni | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Candida albicanse | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Candida glabratae | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Candida parapsilosie | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Candida tropicalise | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Chlamydia trachomatis | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Chromobacterium violaceum | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Citrobacter freundii | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Clostridium difficileb | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Clostridium perfringensb | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Corynebacterium genitalium | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Corynebacterium xerosis | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | ||
| Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | |||
| Cryptococcus neoformanse | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Cryptosporidium parvumc | 1 x 105d | TV NOT DETECTED | TV DETECTED | |
| Cytomegalovirusf | 5 x 105 | TV NOT DETECTED | TV DETECTED | |
| Deinococcus radiodurans | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Derxia gummosa | 1 x 105d | TV NOT DETECTED | TV DETECTED | |
| Eikenella corrodens | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Entamoeba histolyticac | 1 x 105d | TV NOT DETECTED | TV DETECTED | |
| Enterobacter aerogenes | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Enterobacter cloacae | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Enterococcus avium | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Enterococcus faecalis | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Enterococcus faecium | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Erysipelothrix rhusiopathiae | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Escherichia coli | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Flavobacterium meningosepticum | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Fusobacterium nucleatumb | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Gardnerella vaginalis | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Gemella haemolysans | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Giardia intestinalisc | 1 x 105d | TV NOT DETECTED | TV DETECTED | |
| Haemophilus ducreyi | 1 x 105d | TV NOT DETECTED | TV DETECTED | |
| Haemophilus influenzae | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Herpes simplex virus If | 1 x 105 | TV NOT DETECTED | TV DETECTED | |
| Herpes simplex virus IIf | 1 x 105 | TV NOT DETECTED | TV DETECTED | |
| HIV-1f | 2 x 105 | TV NOT DETECTED | TV DETECTED | |
| Human papilloma virus 16f | 6 x 105 | TV NOT DETECTED | TV DETECTED | |
| Kingella dentrificans | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Kingella kingae | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Klebsiella oxytoca | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Klebsiella pneumoniae | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Lactobacillus acidophilus | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Lactobacillus brevis | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Lactobacillus crispatus | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | ||
| Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | |||
| Lactobacillus jensonii | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Lactobacillus lactis | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Lactobacillus vaginalis | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Legionella pneumophila | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Leuconostoc paramensenteroides | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Listeria monocytogenes | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Micrococcus luteus | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Mobiluncus curtisiib | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Moraxella lacunata | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Moraxella osloensis | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Morganella morganii | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Mycobacterium smegmatis | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Mycoplasma genitalium | 1 x 106d | TV NOT DETECTED | TV DETECTED | |
| Mycoplasma hominis | 1 x 106d | TV NOT DETECTED | TV DETECTED | |
| Neisseria cinerea | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria dentrificans | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria elongata | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria flava | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria flavescens | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria gonorrhoeae | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria lactamica | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria mucosa | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria perflava | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria polysaccharea | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria sicca | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Neisseria subflava | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Pantoea agglomerans | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Paracoccus denitrificans | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Pentatrichomonis hominisc | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Peptostreptococcus anaerobiusb | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Peptostreptococcus productusb | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Plesiomonas shigelloides | 4 x 106 | TV NOT DETECTED | TV DETECTED | |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | ||
| Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | |||
| Prevotella biviab | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Propionibacterium acnesb | 3 x 106 | TV NOT DETECTED | TV DETECTED | |
| Proteus mirabilis | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Proteus vulgaris | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Providencia stuartii | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Pseudomonas aeruginosa | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Pseudomonas fluorescens | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Pseudomonas putida | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Rahnella aquatilis | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Rhodospirillum rubrum | 1 x 106d | TV NOT DETECTED | TV DETECTED | |
| Saccharomyces cerevisiaee | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Salmonella minnesota | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Salmonella typhimurium | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Serratia marcescens | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Staphylococcus aureus | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Staphylococcus epidermidis | 7 x 106 | TV NOT DETECTED | TV DETECTED | |
| Staphylococcus saprophyticus | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus agalactiae | 1 x 107 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus bovis | 8 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus mitis | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus mutans | 2 x 107 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus pneumoniae | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus pyogenes | 2 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus salivarius | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptococcus sanguis | 5 x 106 | TV NOT DETECTED | TV DETECTED | |
| Streptomyces griseinus | 6 x 106 | TV NOT DETECTED | TV DETECTED | |
| Trichomonas tenaxc | 1 x 105 | TV DETECTED | TV DETECTED | |
| Trichomonas tenaxc | 1 x 103 | TV DETECTED | TV DETECTED | |
| Trichomonas tenaxc | 1 x 102 | TV NOT DETECTED | TV DETECTED | |
| Ureaplasma parvum | 1 x 106d | TV NOT DETECTED | TV DETECTED | |
| Ureaplasma urealyticum | 1 x 106 | TV NOT DETECTED | TV DETECTED | |
| Vibrio parahaemolyticus | 9 x 106 | TV NOT DETECTED | TV DETECTED | |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | ||
| Cross-Reactivity(- T. vaginalis ) | CompetitiveInterference(+ T. vaginalis ) | |||
| Yersinia enterocolitica | 8 x 106 | TV NOT DETECTED | TV DETECTED |
Table 5-4: Analytical Specificity/Competitive Interference Determination for Xpert TV Assay in Urine Matrix
{12}------------------------------------------------
{13}------------------------------------------------
{14}------------------------------------------------
{15}------------------------------------------------
a. Tests run ≥ 10° CFU/mL for bacteria and fungi, ≥10° genomes/mL for yeast, ≥10° TCIDsy/mL or ≥10° genomes/mL for viruses and ≥105 cells/mL for protozoans.
b. Anaerobic organism
c. Protozoan
d. Genome equivalents tested (DNA)
e. Fungal organism
f. Virus
| Table 5-5: Analytical Specificity/Competitive Interference Determination for |
|---|
| Xpert TV Assav in Vaginal Swab Matrix |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | |
|---|---|---|---|
| Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | ||
| Achromobacter xerosis | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Acinetobacter calcoaceticus | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Acinetobacter lwoffii | 6 x 106 | TV NOT DETECTED | TV DETECTED |
| Actinomyces israeliib | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Actinomyces pyogenes | 8 x 106 | TV NOT DETECTED | TV DETECTED |
| Aerococcus viridans | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Aeromonas hydrophila | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Alcaligenes faecalis | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Atopobium vaginaeb | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Bacillus subtilis | 6 x 106 | TV NOT DETECTED | TV DETECTED |
| Bacteroides fragilisb | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Bacteroides ureolyticusb | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Bifidobacterium adolescentisb | 6 x 106 | TV NOT DETECTED | TV DETECTED |
| Bifidobacterium brevi (breve)b | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Blastocystis hominisc | 1 x 105 d | TV NOT DETECTED | TV DETECTED |
| Branhamella catarrhalis | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Brevibacterium linens | 8 x 106 | TV NOT DETECTED | TV DETECTED |
| Campylobacter jejuni | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Candida albicanse | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Candida glabratae | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Candida parapsilosie | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| ConcentrationTesteda | Xpert TV Assay Result | ||
| Microorganism | Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | |
| Candida tropicalise | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Chlamydia trachomatis | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Chromobacterium violaceum | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Citrobacter freundii | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Clostridium difficileb | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Clostridium perfringensb | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Corynebacterium genitalium | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Corynebacterium xerosis | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Cryptococcus neoformanse | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Cryptosporidium parvumc | 1 x 105 d | TV NOT DETECTED | TV DETECTED |
| Cytomegalovirusf | 5 x 105 | TV NOT DETECTED | TV DETECTED |
| Deinococcus radiodurans | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Derxia gummosa | 1 x 106 d | TV NOT DETECTED | TV DETECTED |
| Eikenella corrodens | 8 x 106 | TV NOT DETECTED | TV DETECTED |
| Entamoeba histolyticac | 1 x 105 d | TV NOT DETECTED | TV DETECTED |
| Enterobacter aerogenes | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Enterobacter cloacae | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Enterococcus avium | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Enterococcus faecalis | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Enterococcus faecium | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Erysipelothrix rhusiopathiae | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Escherichia coli | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Flavobacteriummeningosepticum | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Fusobacterium nucleatumb | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Gardnerella vaginalis | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Gemella haemolysans | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Giardia intestinalisc | 1 x 105 d | TV NOT DETECTED | TV DETECTED |
| Haemophilus ducreyi | 1 x 106 d | TV NOT DETECTED | TV DETECTED |
| Haemophilus influenzae | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Herpes simplex virus If | 1 x 105 | TV NOT DETECTED | TV DETECTED |
| Herpes simplex virus IIf | 1 x 105 | TV NOT DETECTED | TV DETECTED |
| HIV-1f | 2 x 105 | TV NOT DETECTED | TV DETECTED |
| ConcentrationTesteda | Xpert TV Assay Result | ||
| Microorganism | Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | |
| Human papilloma virus 16f | 6 x 105 | TV NOT DETECTED | TV DETECTED |
| Kingella dentrificans | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Kingella kingae | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Klebsiella oxytoca | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Klebsiella pneumoniae | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Lactobacillus acidophilus | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Lactobacillus brevis | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Lactobacillus crispatus | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Lactobacillus jensonii | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Lactobacillus lactis | 1 x 107 | TV NOT DETECTED | TV DETECTED |
| Lactobacillus vaginalis | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Legionella pneumophila | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Leuconostocparamensenteroides | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Listeria monocytogenes | 8 x 106 | TV NOT DETECTED | TV DETECTED |
| Micrococcus luteus | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Mobiluncus curtisiib | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Moraxella lacunata | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Moraxella osloensis | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Morganella morganii | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Mycobacterium smegmatis | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Mycoplasma genitalium | 1 x 106d | TV NOT DETECTED | TV DETECTED |
| Mycoplasma hominis | 1 x 106d | TV NOT DETECTED | TV DETECTED |
| Neisseria cinerea | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria dentrificans | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria elongata | 8 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria flava | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria flavescens | 8 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria gonorrhoeae | 6 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria lactamica | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria mucosa | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria perflava | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria polysaccharea | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | |
| Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | ||
| Neisseria sicca | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Neisseria subflava | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Pantoea agglomerans | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Paracoccus denitrificans | 6 x 106 | TV NOT DETECTED | TV DETECTED |
| Pentatrichomonis hominisc | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Peptostreptococcus anaerobiusb | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Peptostreptococcus productusb | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Plesiomonas shigelloides | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Prevotella biviab | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Propionibacterium acnesb | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Proteus mirabilis | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Proteus vulgaris | 7 x 106 | TV NOT DETECTED | TV DETECTED |
| Providencia stuartii | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Pseudomonas aeruginosa | 4x 106 | TV NOT DETECTED | TV DETECTED |
| Pseudomonas fluorescens | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Pseudomonas putida | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Rahnella aquatilis | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Rhodospirillum rubrum | 1 x 106d | TV NOT DETECTED | TV DETECTED |
| Saccharomyces cerevisiaee | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Salmonella minnesota | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Salmonella typhimurium | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Serratia marcescens | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Staphylococcus aureus | 9 x 106 | TV NOT DETECTED | TV DETECTED |
| Staphylococcus epidermidis | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Staphylococcus saprophyticus | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus agalactiae | 6 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus bovis | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus mitis | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus mutans | 5 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus pneumoniae | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus pyogenes | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptococcus salivarius | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Microorganism | ConcentrationTesteda | Xpert TV Assay Result | |
| Cross-Reactivity(- T. vaginalis) | CompetitiveInterference(+ T. vaginalis) | ||
| Streptococcus sanguis | 2 x 106 | TV NOT DETECTED | TV DETECTED |
| Streptomyces griseinus | 4 x 106 | TV NOT DETECTED | TV DETECTED |
| Trichomonas tenaxc | 1 x 105 | TV DETECTED | TV DETECTED |
| Trichomonas tenaxc | 1 x 103 | TV DETECTED | TV DETECTED |
| Trichomonas tenaxc | 1 x 102 | TV NOT DETECTED | TV DETECTED |
| Ureaplasma parvum | 1 x 106d | TV NOT DETECTED | TV DETECTED |
| Ureaplasma urealyticum | 1 x 106 | TV NOT DETECTED | TV DETECTED |
| Vibrio parahaemolyticus | 3 x 106 | TV NOT DETECTED | TV DETECTED |
| Yersinia enterocolitica | 3 x 106 | TV NOT DETECTED | TV DETECTED |
{16}------------------------------------------------
{17}------------------------------------------------
{18}------------------------------------------------
{19}------------------------------------------------
a. Tests run ≥ 10° CFU/mL for bacteria and fungi, ≥10° genomes/mL for yeast, ≥10° TCIDs0/mL or ≥10° genomes/mL for viruses and ≥10° cells/mL for protozoans.
b. Anaerobic organism
c. Protozoan
d. Genome equivalents tested (DNA)
e. Fungal organism
f. Virus
Additional three microorganisms, Dientamoeba fragilis, Agrobacterium radiobacter, and Erwinia herbicola, were not available for direct testing. An in silico analysis was conducted using the Basic Local Alignment Search Tool (BLAST) to compare the Xpert TV Assay primer and probe sequences with all available sequences associated with these three microorganisms in the GenBank database. Available sequence data for D. fragilis was examined and showed a maximum of 7% homology to the Xpert TV primer and probe sequences. Available sequence data for A. radiobacter was examined and showed a maximum of 38% homology to the Xpert TV primer and probe sequences. Available sequence data for E. herbicola was examined and showed a maximum of 10% homology to the Xpert TV primer and probe sequences. Results are shown in Table 5-6.
| Strain | Accession Number | % Homology |
|---|---|---|
| Dientamoeba fragilis | KC967121.1 | 7% |
| Agrobacterium radiobacter | CP000629.1 | 38% |
| Erwinia herbicola | NG_035384.1 | 10% |
Table 5-6. In silico Analytical Specificity Determination for Xpert TV Assay
Analytical Reactivity (Inclusivity)
The analytical inclusivity of the Xpert TV Assay was evaluated by testing 17 T. vaginalis strains diluted in either negative pooled vaginal swab matrix in Cepheid Xpert Swab Transport Reagent or negative pooled urine in Cepheid Xpert Urine Transport Reagent. All T. vaginalis strains were tested in triplicate at a concentration of 3X the
{20}------------------------------------------------
analytical LoD for the respective specimen type (6 cells/mL for vaginal swabs and 7.5 cells/mL for urine). All strains tested were reported as TV DETECTED. Results are shown in Table 5-7. Positive and negative controls were included in the study. The inclusivity for the 17 T. vaginalis strains tested was 100%.
| Isolate ATCC # | Isolation Source | Results VaginalSwab | Results Urine |
|---|---|---|---|
| 30001 | Vaginal exudate | TV DETECTED | TV DETECTED |
| 30184 | Vaginal swab | TV DETECTED | TV DETECTED |
| 30187 | Endocervical swab | TV DETECTED | TV DETECTED |
| 30188 | Vagina | TV DETECTED | TV DETECTED |
| 30236 | Endocervical swab | TV DETECTED | TV DETECTED |
| 30240 | Vaginal pool | TV DETECTED | TV DETECTED |
| 30245 | Vaginal andEndocervical material | TV DETECTED | TV DETECTED |
| 30247 | Vagina | TV DETECTED | TV DETECTED |
| 50138 | human | TV DETECTED | TV DETECTED |
| 50139 | human | TV DETECTED | TV DETECTED |
| 50141 | human | TV DETECTED | TV DETECTED |
| 50143 | human | TV DETECTED | TV DETECTED |
| 50147 | human | TV DETECTED | TV DETECTED |
| 50167 | Vagina | TV DETECTED | TV DETECTED |
| 50183 | Prostatic fluid | TV DETECTED | TV DETECTED |
| PRA-95 | Vaginal exudate | TV DETECTED | TV DETECTED |
| PRA-98 | human | TV DETECTED | TV DETECTED |
Table 5-7: Analytical Reactivity (Inclusivity) of Xpert TV Assav
Interfering Substances Study
The performance of the Xpert TV Assay was evaluated with potentially interfering endogenous and exogenous substances that may be present in the urogenital tract.
All substances were tested in the presence and absence of 3X LoD T. vaginalis (ATCC strain 30001) to determine if there was interference with the Xpert TV Assay. Substances were individually diluted into either pooled Trichomonas vaginalisnegative urine matrix (patient urine added to Cepheid Urine Transport Reagent) or pooled Trichomonas vaginalis-negative vaginal swab matrix (vaginal swabs collected into Cepheid Swab Transport Reagent). Positive and negative controls were included in the study.
For each interfering substance, eight replicates were tested for each set of samples (either T. vaginalis negative or T. vaginalis positive in clinical matrix). Tables 5-8 and 5-9 show the substances that were tested, the test concentrations, and the matrix in which they were diluted. One substance, blood at > 60% v/v demonstrated interference (result of TV NOT DETECTED in the presence of TV) in the vaginal swab matrix samples. Blood was subjected to repeat analysis at various lower concentrations until a result of TV
{21}------------------------------------------------
DETECTED was obtained (50% v/v). For the other conditions and substances tested, all TV positive samples remained positive and all TV negative samples remained negative, indicating that there was no interference causing false negative or false positive results with the Xpert TV Assay for these substances.
| Class/Substance | Active Ingredient | Concentration Tested |
|---|---|---|
| Blood | Blood | 0.3% v/v, 1% v/v |
| Seminal Fluid | Seminal Fluid | 5.0% v/v |
| Mucus | Mucin | 0.8% w/v |
| Analgesics &Antibiotics | Acetylsalicylic Acid 500mg | 40 mg/mL |
| Acetaminophen | 3.2 mg/mL | |
| Azithromycin | 1.8 mg/mL | |
| Doxycycline | 3.6 mg/mL | |
| OTC Deodorant &Powders | PEG-20; PEG-32;PEG-20 Stearate | 0.25% w/v |
| Nanoxynol-9 | 0.25% w/v | |
| Albumin | BSA | 10 mg/ml |
| Glucose | Glucose | 10 mg/ml |
| Bilirubin | Bilirubin | 1 mg/ml |
| Acidic Urine (pH 4.0) | Urine + N-Acetyl-L-Cysteine | pH 4.0 |
| Alkaline Urine (pH 9.0) | Urine + Ammonium Citrate | pH 9.0 |
| Leukocytes | Leukocytes | 105 cells/mL |
| Intravaginal Hormones | Progesterone; Estradiol | 7 mg/mL Progesterone +0.07 mg/mL Beta Estradiol |
Table 5-8: Potentially Interfering Substances in Urine Samples
Table 5-9: Potentially Interfering Substances in Swab Samples
| Class/Substance | Active Ingredient | Concentration Tested |
|---|---|---|
| Blooda | Blood | 10%, 50%, 60% v/v |
| Seminal Fluid | Seminal Fluid | 5.0% v/v |
| Mucus | Mucin | 0.8% w/v |
| Over the counter (OTC)Vaginal Products;Contraceptives; Vaginaltreatments | Benzocaine 5%;Resorcinol 2% | 0.25% w/v |
| Clotrimazole 2% | 0.25% w/v | |
| Miconazole Nitrate 2% | 0.25% w/v | |
| Tioconazole | 0.25% w/v | |
| 5% w/w Aciclovir | 0.25% w/v | |
| Glycerin, Propylene glycol | 0.25% w/v | |
| Glycerin; Carbomer | 0.12% w/v | |
| Glycerin, Hydroxyethyl cellulose | 0.25% w/v | |
| Goldenseal 3X HPUS;Kreosotum 12X HPUS | 0.25% w/v | |
| Povidone-iodine 10% | 0.25% v/v | |
| Nonoxynol-9 12.5% | 0.25% w/v |
{22}------------------------------------------------
| Class/Substance | Active Ingredient | Concentration Tested |
|---|---|---|
| Hemorrhoidal Cream | Glycerin 14%;Pramoxine HCl 1% | 0.25% w/v |
| Leukocytes | Leukocytes | $10^5$ cells/mL |
| Intravaginal Hormones | Progesterone; Estradiol | 7 mg/mL Progesterone +0.07 mg/mL Beta Estradiol |
a. In tests with substances diluted into pooled T. vaginalis-positive swab matrix, assay interference was observed in tests with blood at 60% v/v. No assay interference was observed in tests with blood at 50% v/v. This is addressed in Limitations in the package insert.
Carry-Over Contamination
This study was conducted to demonstrate that single-use, self-contained GeneXpert cartridges prevent carry-over contamination in negative samples run after very high positive samples in the same GeneXpert module. A negative sample (T. vaginalis negative vaginal swabs in Cepheid Xpert Swab Transport Reagent) was run followed by 20 rounds of high positive sample (T. vaginalis ATCC 30001 at 10° cells/mL diluted in vaginal swab matrix) alternating with a negative sample in two separate GeneXpert modules for a total of 40 high positive and 42 negative samples for each module. This testing scheme resulted in a total of 82 runs (40 positive + 42 negative single-use samples). There was no evidence of carry-over contamination as all 40 positive samples were correctly reported as TV DETECTED and all 42 negative samples were correctly reported as TV NOT DETECTED.
Linearity
Not applicable, the Xpert TV Assay is a qualitative assay.
Clinical Studies
Clinical Performance
Performance characteristics of the Xpert TV Assay were determined in a multi-site prospective investigational study by comparing the results from the Xpert TV Assay to a patient infected status (PIS) algorithm comprised of culture and validated bidirectional sequencing (primary sequencing) for male urine, or an FDA cleared NAAT test and culture for female specimen types.
Study participants included consenting asymptomatic and symptomatic, sexually active males and females seen at locations including, but not limited to: OB/GYN, sexually transmitted disease (STD), and family planning clinics. The average age among eligible female study participants was 33.5 years (range = 18 to 78 years). The average age among eligible male study participants was 36.2 years (range = 16 to 78 years).
The study specimens consisted of prospectively collected male urine, endocervical swabs, and patient-collected vaginal swabs (collected in a clinical setting). Clinician-collected vaginal swabs were collected for testing by the reference NAAT test and culture. Samples were collected from 17 clinical sites and tested at 11 sites. Reference testing was performed at 3 central laboratories.
A study participant was considered to be infected by PIS if either of the two reference
{23}------------------------------------------------
test results were positive. The subject was considered to be not infected by PIS when both reference test results were negative.
Performance of the Xpert TV Assay was calculated relative to the PIS for each of the three female specimen types (endocervical swabs, patient-collected vaginal swabs and urine) or to the PIS for male urine, respectively.
Specimens with discrepant results between the Xpert TV Assay and the PIS were analyzed by validated bi-directional Sanger sequencing and results are footnoted in Table 5-10 for informational purposes only.
Among the 10,017 tests performed, 190 had initial ERROR, INVALID, or NO RESULT outcomes (1.90%, 95% CI 1.65-2.18). Of those, 167 specimens yielded valid results upon repeat assay (7 specimens were not retested). The overall valid reporting rate of the assay was 99.8% (9994/10,017).
Results of the Xpert TV Assay were compared to the PIS for determination of sensitivity, specificity, and predictive values. Sensitivity and specificity for TV by specimen type and symptom status are presented in Table 5-10.
{24}------------------------------------------------
| Sample Type | Status | Total (n) | Sens | 95% CI | Spec | 95% CI | Prev (%) | PPV (%) | NPV (%) |
|---|---|---|---|---|---|---|---|---|---|
| ES | Symp | 685 | 100%(71/71) | 94.9%-100% | 98.5%(605/614) | 97.2%-99.3% | 10.4% | 88.8% | 100% |
| Asymp | 1114 | 98.1%(104/106) | 93.4%-99.8% | 99.1%(999/1008) | 98.3%-99.6% | 9.5% | 92.0% | 99.8% | |
| Overall | 1799 | 98.9%(175/177)a | 96.0%-99.9% | 98.9%(1604/1622)b | 98.3%-99.3% | 9.8% | 90.7% | 99.9% | |
| Difference | P-Value | P=0.517 | -0.70%, 4.48% | P=0.331 | -1.69%, 0.54% | ||||
| Symp | 682 | 98.6%(73/74) | 92.7%-100% | 99.5%(605/608) | 98.6%-99.9% | 10.9% | 96.1% | 99.8% | |
| PC-VS | Asymp | 1109 | 95.0%(113/119) | 89.3%-98.1% | 99.6%(986/990) | 99.0%-99.9% | 10.7% | 96.6% | 99.4% |
| Overall | 1791 | 96.4%(186/193)c | 92.7%-98.5% | 99.6%(1591/1598)d | 99.1%-99.8% | 10.8% | 96.4% | 99.6% | |
| Difference | P-Value | P=0.254 | -1.04%, 8.42% | P=1.000 | -0.77%, 0.59% | ||||
| Symp | 688 | 98.6%(71/72) | 92.5%-100% | 99.8%(615/616) | 99.1%-100% | 10.5% | 98.6% | 99.8% | |
| UR-F | Asymp | 1105 | 98.2%(109/111) | 93.6%-99.8% | 99.6%(990/994) | 99.0%-99.9% | 10.0% | 96.5% | 99.8% |
| Overall | 1793 | 98.4%(180/183)e | 95.3%-99.7% | 99.7%(1605/1610)f | 99.3%-99.9% | 10.2% | 97.3% | 99.8% | |
| Difference | P-Value | P=1.000 | -3.25%, 4.08% | P=0.655 | -0.27%, 0.75% | ||||
| Symp | 1088 | 87.5%(28/32) | 71.9%-95.0% | 99.8%(1054/1056) | 99.3%-99.9% | 2.9% | 93.3% | 99.6% | |
| UR-M | Asymp | 3523 | 90.3%(84/93) | 82.6%-94.8% | 99.2%(3401/3430) | 98.8%-99.4% | 2.6% | 74.3% | 99.7% |
| Overall | 4611 | 89.6%(112/125)g | 83.0%-93.8% | 99.3%(4455/4486)h | 99.0%-99.5% | 2.7% | 78.3% | 99.7% | |
| Difference | P=0.738 | -15.8%, 10.1% | P=0.020 | 0.25%, 1.06% |
Table 5-10: Xpert TV vs. PIS by Symptomatic Status
TP=tne positive, PP=false positive, TN=false negative, ES=ndocervical swab, PC-VS=patient-ollected vaginal swab, UR-M=rale urne a. Testing results by sequencing: 1 of 2 FN was TV positive; 1 of 2 was TV negative.
b. Testing results by sequencing: 8 of 18 FP were TV positive; 10 of 18 were TV negative.
c. Testing results by sequencing: 3 of 7 FN were TV positive; 4 of 7 were TV negative.
d. Testing results by sequencing: 5 of 7 FP were TV positive; 2 of 7 were TV negative.
e. Testing results by sequencing: 3 of 3 FN were TV negative.
f. Testing results by sequencing: 5 of 5 FP were TV negative.
g. Testing results by secondary sequencing: 9 of 13 false negative; 4 of 13 were TV positive.
h. Testing results by secondary sequencing: 27 of 31 false positive; 4 of 31 were TV negative.
{25}------------------------------------------------
Cycle Threshold (Ct) Frequency Distribution
Patient-collected vaginal swabs, endocervical swabs and urine specimens were collected from 1867 females and urine specimens were collected from 4626 males at 17 collection sites in the US. The frequency distribution of Xpert TV Assay positive results for the 197 Trichomonas vaginalis infected female study subjects and 125 Trichomonas vaginalis infected male study subjects are shown in Figure 5-1.
Image /page/25/Figure/2 description: The image is a histogram displaying the distribution of Ct values. The x-axis represents Ct values, ranging from 10 to 40, while the y-axis represents the number of specimens, ranging from 0 to 60. The histogram shows a distribution that peaks between Ct values of 25 and 30, indicating that most specimens have Ct values within this range. The number of specimens decreases as Ct values move away from this peak in either direction.
Figure 5-1: Ct Distribution of Patients Designated as Positive for TV Based on PIS Algorithm
Reproducibility Study
Intra-site reproducibility of the Xpert TV Assay was evaluated at three sites (two external, one in-house). Site 1 used an Infinity-80 instrument. Sites 2 and 3 used GeneXpert Dx instruments. Specimens were created by spiking Trichomonas vaginalis (ATCC® 30001™) into pooled, Trichomonas vaginalis negative urine (patient urine added to Cepheid Urine Transport Reagent) or vaginal swab matrix (vaginal swabs collected into Cepheid Swab Transport Reagent). The specimens were prepared at concentration levels representing high negative (below LoD), LoD (~1X LoD), moderate positive (~3X LoD), and negative (Trichomonas vaginalis negative clinical matrix). A panel of 8 specimens (4 in urine and 4 in vaginal swab matrix) was tested twice per day. on 12 different days, by two different operators, at each of three sites (8 specimens x 2 replicates x 12 days x 2 operators x 3 sites = 1,152 observations total). Three lots of Xpert TV Assay cartridges were used at each of the 3 testing sites, with each lot used for 4 days of testing. Positive and negative controls were included in the study. The Xpert TV Assay was performed according to the Xpert TV Assay procedure. The rate of agreement with expected results is shown by site in Table 5-11.
{26}------------------------------------------------
| Samplea | Site 1(Infinity-80) | Site 2(GeneXpert Dx) | Site 3(GeneXpert Dx) | TotalAgreementby Sample | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Op 1 | Op 2 | Site | Op 1 | Op 2 | Site | Op 1 | Op 2 | Site | ||
| FS-Neg | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(144/144) |
| FS-Mod Pos(~3X LoD;~6 cells/mL) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(144/144) |
| FS-LoD(~1X LoD;~2 cells/mL) | 95.8%(23/24) | 100%(24/24) | 97.9%(47/48) | 87.5%(21/24) | 95.8%(23/24) | 91.7%(44/48) | 100%(24/24) | 95.8%(23/24) | 97.9%(47/48) | 95.8%(138/144) |
| FS-High Neg(below LoD;< 2 cells/mL) | 87.5%(21/24) | 75.0%(18/24) | 81.3%(39/48) | 66.7%(16/24) | 79.2%(19/24) | 72.9%(35/48) | 79.2%(19/24) | 70.8%(17/24) | 75.0%(36/48) | 76.4%(110/144) |
| UR-Neg | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(144/144) |
| UR-Mod Pos(~3X LoD;~9 cells/mL) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(24/24) | 100%(24/24) | 100%(48/48) | 100%(144/144) |
| UR-LoD(~1X LoD;~3 cells/mL) | 75.0%(18/24) | 91.7%(22/24) | 83.3%(40/48) | 83.3%(20/24) | 91.3%(21/23)b | 87.2%(41/47) | 91.7%(22/24) | 100%(24/24) | 95.8%(46/48) | 88.8%(127/143) |
| UR-High Neg(below LoD; <3 cells/mL) | 75.0%(18/24) | 75.0%(18/24) | 75.0%(36/48) | 70.8%(17/24) | 54.2%(13/24) | 62.5%(30/48) | 75.0%(18/24) | 75.0%(18/24) | 75.0%(36/48) | 70.8%(102/144) |
Table 5-11: Summary of Reproducibility Results
a. FS=female swab matrix; UR=male urine matrix.
b. One sample indeterminate on initial and retest.
The reproducibility of the Xpert TV Assay was also evaluated in terms of the fluorescence signal expressed in Ct values for each target detected. The mean, standard deviation (SD), and coefficient of variation (CV) between-sites, between-lots, between days, between-operators, and residual variability for each panel member are presented in Table 5-12.
{27}------------------------------------------------
| Samplea | AssayChannel(Analyte) | Nb | MeanCt | Between-Site | Between-Lot | Between-Day | Between-Operator | Residual | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | ||||
| FS-Neg | SPC | 144 | 33.7 | 0.0 | 0.0 | 0.1 | 23.2 | 0.1 | 8.9 | 0.0 | 0.0 | 0.4 | 67.9 | 0.4 | 1.2 |
| FS-Mod Pos(~3X LoD;~6 cells/mL) | TV | 144 | 35.4 | 0.1 | 7.9 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 12.5 | 0.8 | 79.7 | 0.8 | 2.3 |
| FS-LoD( | TV | 138 | 38.5 | 0.0 | 0.0 | 0.0 | 0.0 | 0.5 | 28.0 | 0.0 | 0.0 | 1.2 | 72.0 | 1.3 | 3.5 |
| FS-High Neg(below LoD;< 2 cells/mL) | TV | 110 | 39.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.4 | 17.6 | 0.0 | 0.0 | 1.7 | 82.4 | 1.8 | 4.5 |
| UR-Neg | SPC | 144 | 33.9 | 0.1 | 8.6 | 0.0 | 0.0 | 0.1 | 9.0 | 0.1 | 18.5 | 0.4 | 63.9 | 0.4 | 1.2 |
| UR-Mod Pos(~3X LoD;~9 cells/mL) | TV | 144 | 35.5 | 0.2 | 22.3 | 0.1 | 9.6 | 0.0 | 0.0 | 0.0 | 0.0 | 0.6 | 67.9 | 0.7 | 1.9 |
| UR-LoD(~1X LoD;~3 cells/mL) | TV | 127 | 39.3 | 0.0 | 0.0 | 0.4 | 24.4 | 0.0 | 0.0 | 0.0 | 0.0 | 1.2 | 75.6 | 1.3 | 3.4 |
| UR-High Neg(below LoD;<3 cells/mL) | TV | 102 | 39.0 | 0.0 | 0.0 | 0.3 | 14.4 | 0.7 | 29.5 | 0.3 | 11.6 | 1.0 | 44.6 | 1.3 | 3.3 |
Table 5-12: Summary of Reproducibility Data
a. FS=female swab matrix; UR= urine matrix.
b. Results with non-zero Ct values out of 144.
c. (%) is contribution of variance component to overall CV.
Instrument System Precision
An in-house precision study was conducted to compare the performance of the GeneXpert Dx and the GeneXpert Infinity Instrument Systems using specimens comprised of Trichomonas vaginalis (ATCC® 30001™) spiked into negative urine (patient urine added to Cepheid Urine Transport Reagent) or vaginal swab matrix (vaginal swabs collected into Cepheid Swab Transport Reagent). The specimens were prepared at concentration levels representing high negative (below LoD), LoD (~1X LoD), moderate positive (~3X LoD), and negative (Trichomonas vaginalis negative clinical matrix). A panel of 8 specimens (4 in urine matrix and 4 in vaginal swab matrix) was tested on 12 different days by two operators. Each operator conducted four runs of each panel specimen per day on each of the three instrument systems (8 specimens x 4 times/day x 12 days x 2 operators x 3 instrument systems = 2.304 observations total). Three lots of Xpert TV Assay cartridges were used for the study, with each lot used for 4 days of testing. Positive and negative controls were included in the study. The Xpert TV Assay was performed according to the Xpert TV Assay procedure. The rate of agreement with expected results is shown by instrument in Table 5-13.
{28}------------------------------------------------
| Samplea | GeneXpert Dx | Infinity-48 | Infinity-80 | % TotalAgreementby Sample | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Op 1 | Op 2 | Inst | Op 1 | Op 2 | Inst | Op 1 | Op 2 | Inst | |||||
| FS-Neg | 100%(48/48) | 100%(48/48) | 100%(96/96) | 97.9%(47/48) | 100%(48/48) | 99.0%(95/96) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 99.7%(287/288) | |||
| FS-Mod Pos(~3X LoD;~6 cells/mL) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(288/288) | |||
| FS-LoD( | 93.8%(45/48) | 87.5%(42/48) | 90.6%(87/96) | 93.8%(45/48) | 89.6%(43/48) | 91.7%(88/96) | 95.8%(46/48) | 89.6%(43/48) | 92.7%(89/96) | 91.7%(264/288) | |||
| FS-High Neg(below LoD;< 2 cells/mL) | 74.5%(35/47) | 75.0%(36/48) | 74.7%(71/95) | 77.1%(37/48) | 75.0%(36/48) | 76.0%(73/96) | 83.3%(40/48) | 68.8%(33/48) | 76.0%(73/96) | 75.6%(217/287)b | |||
| UR-Neg | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(48/48) | 100%(47/47) | 100%(95/95) | 100%(287/287)b | |||
| UR-Mod Pos(~3X LoD;~9 cells/mL) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(48/48) | 100%(48/48) | 100%(96/96) | 100%(288/288) | |||
| UR-LoD(~1X LoD;~3 cells/mL) | 93.8%(45/48) | 93.8%(45/48) | 93.8%(90/96) | 95.8%(46/48) | 89.6%(43/48) | 92.7%(89/96) | 95.8%(46/48) | 95.8%(46/48) | 95.8%(92/96) | 94.1%(271/288) | |||
| UR-High Neg(below LoD;< 3 cells/mL) | 72.9%(35/48) | 77.1%(37/48) | 75.0%(72/96) | 70.8%(34/48) | 79.2%(38/48) | 75.0%(72/96) | 81.3%(39/48) | 85.4%(41/48) | 83.3%(80/96) | 77.8%(224/288) |
Table 5-13: Summary of Precision Results
a. FS=female swab matrix; UR=male urine matrix.
b. One FS-Low Pos and one UR-Neg sample indeterminate and not retested.
The precision of the Xpert TV Assay was also evaluated in terms of the fluorescence signal expressed in Ct values for each target detected. The mean, standard deviation (SD), and coefficient of variation (CV) between-instruments, between-lots, between-days, between-operators, and residual variability for each panel member are presented in Table 5-14.
{29}------------------------------------------------
| Samplea | AssayChannel(Analyte) | Nb | MeanCt | Between-Instrument | Between-Lot | Between-Day | Between-Operator | Residual | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | SD | CV(%)c | ||||
| FS-Neg | SPC | 288 | 31.9 | 0.0 | 0.0 | 0.3 | 53.5 | 0.0 | 0.0 | 0.1 | 1.9 | 0.2 | 44.6 | 0.4 | 1.1 |
| FS-Mod Pos(~3X LoD;~6 cells/mL) | TV | 288 | 35.2 | 0.0 | 0.0 | 0.3 | 22.4 | 0.0 | 0.0 | 0.1 | 4.5 | 0.4 | 73.1 | 0.5 | 1.5 |
| FS-LoD( | TV | 264 | 39.0 | 0.2 | 3.3 | 0.1 | 0.4 | 0.2 | 1.3 | 0.0 | 0.0 | 1.3 | 95.0 | 1.3 | 3.4 |
| FS-High Neg(below LoD;< 2 cells/mL) | TV | 217 | 39.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 1.6 | 1.3 | 98.4 | 1.3 | 3.2 |
| UR-Neg | SPC | 287 | 32.4 | 0.0 | 0.0 | 0.3 | 47.2 | 0.1 | 2.9 | 0.0 | 0.0 | 0.3 | 49.9 | 0.4 | 1.2 |
| UR-Mod Pos(~3X LoD;~9 cells/mL) | TV | 288 | 35.4 | 0.0 | 0.0 | 0.4 | 30.4 | 0.0 | 0.0 | 0.2 | 11.3 | 0.5 | 58.3 | 0.6 | 1.8 |
| UR-LoD(~1X LoD;~3 cells/mL) | TV | 271 | 38.2 | 0.0 | 0.0 | 0.5 | 13.6 | 0.6 | 16.2 | 0.3 | 3.6 | 1.2 | 66.5 | 1.4 | 3.7 |
| UR-High Neg(below LoD;< 3 cells/mL) | TV | 224 | 38.9 | 0.0 | 0.0 | 0.3 | 5.4 | 0.0 | 0.0 | 0.3 | 4.2 | 1.2 | 90.3 | 1.3 | 3.3 |
Table 5-14: Summary of Precision Data
a. FS=female swab matrix; UR=urine matrix.
b. Results with non-zero Ct values out of 288.
c. (%) is contribution of variance component to overall CV.
Conclusions
The results of the nonclinical analytical and clinical performance studies summarized above demonstrate that the Xpert TV Assay is substantially equivalent to the predicate device.
§ 866.3860
Trichomonas vaginalis nucleic acid assay.(a)
Identification. ATrichomonas vaginalis nucleic acid assay is a device that consists of primers, probes, enzymes, and controls for the amplification and detection of trichomonas nucleic acids in endocervical swabs, vaginal swabs, and female urine specimens, from women symptomatic for vaginitis, cervicitis, or urethritis and/or to aid in the diagnosis of trichomoniasis in asymptomatic women. The detection of trichomonas nucleic acids, in conjunction with other laboratory tests, aids in the clinical laboratory diagnosis of trichomoniasis caused byTrichomonas vaginalis .(b)
Classification. Class II (special controls). The special controls are set forth in FDA's guideline document entitled: “Class II Special Controls Guideline: Nucleic Acid Amplification Assays for the Detection ofTrichomonas vaginalis; Guideline for Industry and Food and Drug Administration Staff.” See § 866.1(e) for information on obtaining this document.