BD PROBETEC NEISSERIA GONORRHOEAE (GC) Q AMPLIFIED DNA ASSAY
Device Facts
| Record ID | K081825 |
|---|---|
| Device Name | BD PROBETEC NEISSERIA GONORRHOEAE (GC) Q AMPLIFIED DNA ASSAY |
| Applicant | Becton, Dickinson & CO |
| Product Code | LSL · Microbiology |
| Decision Date | Dec 11, 2008 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 866.3390 |
| Device Class | Class 2 |
| Attributes | Real-World Evidence |
Real-World Evidence
| Submission | Device | Sponsor | RWD Sources | RWE Use Summary | Key Tags |
|---|---|---|---|---|---|
| K081825 · Dec 11, 2008 | BD PROBETEC NEISSERIA GONORRHOEAE (GC) Q AMPLIFIED DNA ASSAY | Becton, Dickinson & CO | Clinical specimens (endocervical swabs, urethral swabs, vaginal swabs, urine) collected from patients in routine clinical settings (OB/GYN, STD, and family planning clinics) | Clinical performance evaluation (sensitivity and specificity) of the BD ProbeTec GC Qx Assay compared to a patient infected status (PIS) algorithm based on reference NAAT testing. | Clinical performance; Diagnostic accuracy; Routine clinical setting; Multi-site study |
Clinical Evidence
| Study Design | Population | Comparator | Key Endpoints |
|---|---|---|---|
| Multi-site clinical evaluation of diagnostic performance | 1059 female and 479 male subjects attending OB/GYN, STD, and family planning clinics; symptomatic and asymptomatic; Sample Size: 1466 total compliant subjects (994 female, 472 male); Number of Sites: 7 | Patient Infected Status (PIS) algorithm based on two reference NAATs (BD ProbeTec ET GC/AC assay and another commercially available NAAT) | Sensitivity and specificity of the BD ProbeTec GC Qx Assay by specimen type and symptomatic status |
Indications for Use
The BD ProbeTec™ Neisseria gonorrhoeae (GC) Q Amplified DNA Assay, when tested with the BD Viper™ System in Extracted Mode, uses Strand Displacement Amplification technology for the direct, qualitative detection of Neisseria gonorthoeae DNA in clinician-collected female endocervical and male urethral swab specimens, patient-collected vaginal swab specimens (in a clinical setting), and male and female urine specimens (both UPT and Neat). The assay is indicated for use with asymptomatic and symptomatic females and symptomatic males to aid in the diagnosis of gonococcal urogenital disease.
Device Story
Device performs automated DNA extraction and qualitative detection of Neisseria gonorrhoeae DNA. Input: clinician-collected endocervical/urethral swabs, patient-collected vaginal swabs, or urine. Process: specimens undergo chemical lysis; DNA binds to ferric oxide particles via magnetic extraction; purified DNA eluted into SDA-compatible buffer; transferred to priming microwells; reaction mixture moved to amplification microwells; sealed; incubated in thermally-controlled fluorescent readers. System uses Strand Displacement Amplification (SDA). Output: positive, negative, or EC failure result based on peak fluorescence (MaxRFU) compared to threshold. Used in clinical settings; operated by laboratory personnel. Healthcare providers use results to aid in diagnosis of gonococcal urogenital disease, enabling timely clinical decision-making and patient treatment.
Clinical Evidence
Multi-center clinical study (7 sites, 1059 female/479 male subjects). Performance compared to Patient Infected Status (PIS) algorithm using reference NAATs. Total 5387 results analyzed. Overall sensitivity 99.3% (577/581) and specificity 99.4% (4779/4806). Subgroup analysis by specimen type and symptomatic status provided. Analytical performance included reproducibility, LoD (<50-100 cells/mL), and cross-reactivity/interference testing.
Technological Characteristics
Uses Strand Displacement Amplification (SDA) with fluorescently-labeled detector probes. Reagents provided in disposable microwells. Automated processing via BD Viper System using paramagnetic particle extraction. Detects N. gonorrhoeae DNA via MaxRFU thresholding. Includes internal extraction control.
Indications for Use
Indicated for qualitative detection of N. gonorrhoeae DNA in clinician-collected female endocervical/male urethral swabs, patient-collected vaginal swabs, and male/female urine. Population: asymptomatic and symptomatic females, symptomatic males. Aids diagnosis of gonococcal urogenital disease.
Regulatory Classification
Identification
Neisseria spp. direct serological test reagents are devices that consist of antigens and antisera used in serological tests to identify Neisseria spp. from cultured isolates. Additionally, some of these reagents consist of Neisseria spp. antisera conjugated with a fluorescent dye (immunofluorescent reagents) which may be used to detect the presence of Neisseria spp. directly from clinical specimens. The identification aids in the diagnosis of disease caused by bacteria belonging to the genus Neisseria, such as epidemic cerebrospinal meningitis, meningococcal disease, and gonorrhea, and also provides epidemiological information on diseases caused by these microorganisms. The device does not include products for the detection of gonorrhea in humans by indirect methods, such as detection of antibodies or of oxidase produced by gonococcal organisms.
Predicate Devices
Submission Summary (Full Text)
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
A. 510(k) Number: K081825
B. Purpose for Submission: To add the option for automated extraction of DNA from clinical specimens using the software accessory “BD ProbeTec™ Neisseria gonorrhoeae (GC) Q® Amplified DNA Assay” to direct the BD Viper™ System.
C. Measurand: Neisseria gonorrhoeae DNA
D. Type of Test: Qualitative determination of Neisseria gonorrhoeae DNA using the Strand Displacement Amplification (SDA) technology
E. Applicant: BD Diagnostic System
F. Proprietary and Established Names: BD ProbeTec™ Neisseria gonorrhoeae (GC) Q® Amplified DNA Assay
G. Regulatory Information:
| Product Code | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| LSL | Class II | 21CFR 866.3390 Neisseria spp. direct serological test reagents | Microbiology (83) |
H. Intended Use:
1.) Intended use: The BD ProbeTec GC Q® Amplified DNA Assay, when tested with the BD Viper™ System in Extracted Mode, uses Strand Displacement Amplification technology for the direct, qualitative detection of Neisseria gonorrhoeae DNA in clinician-collected female endocervical and male urethral swab specimens, patient-collected vaginal swab specimens (in a clinical setting), and male and female urine specimens. The assay is indicated for use with asymptomatic and symptomatic female individuals and symptomatic male individuals to aid in the diagnosis of gonococcal urogenital disease.
2.) Indications for use: Same as intended use
3) Special conditions for use statement(s): For Prescription use only
4) Special instrument requirements: BD Viper™ System with automated nucleic acid extraction mode
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I. Device Description: The BD ProbeTec GC Q $^{\text{X}}$ Amplified DNA Assay is based on the simultaneous amplification and detection of target DNA using amplification primers and a fluorescently-labeled detector probe. The reagents for SDA are dried in two separate disposable microwells: the Priming Microwell contains the amplification primers, fluorescently-labeled detector probe, nucleotides and other reagents necessary for amplification, while the Amplification Microwell contains the two enzymes (a DNA polymerase and a restriction endonuclease) that are required for SDA. The BD Viper System pipettes a portion of the purified DNA solution from each Extraction Tube into a Priming Microwell to rehydrate the contents. After a brief incubation, the reaction mixture is transferred to a corresponding, pre-warmed Amplification Microwell which is sealed to prevent contamination and then incubated in one of the two thermally-controlled fluorescent readers. The presence or absence of $N$ . gonorrhoeae DNA is determined by calculating the peak fluorescence (Maximum Relative Fluorescent Units (MaxRFU)) over the course of the amplification process and by comparing this measurement to a predetermined threshold value.
In addition to the fluorescent probe used to detect amplified $N$ . gonorrhoeae target DNA, a second labeled oligonucleotide is incorporated in each reaction. The Extraction Control (EC) oligonucleotide is labeled with a different dye than that used for detection of the $N$ . gonorrhoeae -specific target and is used to confirm the validity of the extraction process. The EC is dried in the Extraction Tubes and is rehydrated upon addition of the specimen and extraction reagents. At the end of the extraction process, the EC fluorescence is monitored by the BD Viper System and an automated algorithm is applied to both the EC and $N$ . gonorrhoeae -specific signals to report results as positive, negative, or EC failure.
# J. Substantial Equivalence Information:
a) Predicate device name (s):
BD ProbeTecTm ET CT/NG Amplified DNA Assays Gen-Probe Aptima Combo 2 Assay
b) Predicate Numbers (s): K984631, K003395
Comparison with predicate:
Comparison of Operating and Technological Characteristics
| | BD Viper System: Extracted mode of operation | BD Viper System Non-extracted mode of operation (K052481) |
| --- | --- | --- |
| Thermal Module: • Priming Temperature • Priming to Amplification Transfer Temperature • Amplification Temperature | • Same as BD Viper System K052481 • 70°C • Same as BD Viper System K052481 | • 70°C • 70°C to 52.5°C • 52.5°C |
| Amplification Plate Sealing | • Same as BD Viper System K052481 | • Automated sealing of amplification plate |
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| Optical Module: Fluorescent readers | • Same as BD Viper System K052481
• Same as BD Viper System K052481
• Extraction control read on ROX | • Automatic amplification plate transfer into resident readers (2 readers)
• Target read on FAM channel
• ROX channel not used |
| --- | --- | --- |
| Software Module | | |
| Sample log-in | • Same as BD Viper System K052481
• Patient Sample Location Identification (optional) | • Bar-code or key entered accession numbers |
| Algorithm | • MaxRFU – Maximum (normalized) Relative Fluorescence Units | • MOTA – Method Other Than Acceleration (area under the curve) |
| Menu | • Same as BD Viper System K052481
• Added: CTQ, GCQ and CTQ/GCQ | • CT or CT/GC |
| Controls and System Checks | | |
| Assay Controls | • Positive and negative run controls
• Automated control rehydration
• Extraction control
• Specimen processing control procedure | • Positive and negative run controls
• Manual control rehydration
• Specimen processing control procedure |
| System Checks | • Same as BD Viper System K052481
• Extraction reagent checks
• Liquid Waste reservoir check | • Consumables, Pipettor, Thermal, Optical, Fluid Volumes |
| Waste and Waste Disposal | | |
| • Waste Composition
• Liquid Waste Disposal Container
• Liquid Waste Neutralizer | • Same as BD Viper System K052481 and liquid waste (extraction reagents)
• Modified waste disposal bottle
• Neutralization pouch for liquid waste | • Solid waste (pipette tips)
• Waste disposal bottle resident, not used except in aborted run condition
• NA |
# K. Standard/Guidance Document Referenced (if applicable):
1. Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices, May 11, 2005. http://www.fda.gov/cdrh/ode/guidance/337.pdf
2. CLSI EP5-A2 "Evaluation of Precision Performance of Quantitative Measurement Methods",
3. CLSI EP12-A "User Protocol for Evaluation of Qualitative Test Performance".
# L. Test Principle:
The BD ProbeTec GC Q $^{\text{X}}$ Amplified DNA Assay is designed for use with the BD ProbeTec Chlamydia trachomatis/Neisseria gonorrhoeae (CT/GC) Q $^{\text{X}}$ specimen
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collection and transport devices, applicable reagents, the BD Viper System and BD Fox Extraction. Specimens are collected and transported in their respective transport devices which preserve the integrity of the N. gonorrhoeae DNA over the specified ranges of temperature and time.
Urine and swab specimens undergo a pre-warm step in the BD Viper Lysing Heater to dissolve mucus and homogenize the specimen. After cooling, the specimens are loaded onto the BD Viper System which then performs all the steps involved in extraction and amplification of target DNA, without further user intervention. The specimen is transferred to an Extraction Tube that contains ferric oxide particles in a dissolvable film and dried Extraction Control. A high pH is used to lyse the bacterial cells and liberate their DNA into solution. Acid is then added to lower the pH and induce a positive charge on the ferric oxide, which in turn binds the negatively charged DNA. The particles and bound DNA are then pulled to the sides of the Extraction Tube by magnets and the treated specimen is aspirated to waste. The particles are washed and a high pH Elution Buffer is added to recover the purified DNA. Finally, a Neutralization Buffer is used to bring the pH of the extracted solution to the optimum for amplification of the target.
The BD ProbeTec GC Q® Amplified DNA Assay is based on the simultaneous amplification and detection of target DNA using amplification primers and a fluorescently-labeled detector probe. The reagents for SDA are dried in two separate disposable microwells: the Priming Microwell contains the amplification primers, fluorescently-labeled detector probe, nucleotides and other reagents necessary for amplification, while the Amplification Microwell contains the two enzymes (a DNA polymerase and a restriction endonuclease) that are required for SDA. The BD Viper System pipettes a portion of the purified DNA solution from each Extraction Tube into a Priming Microwell to rehydrate the contents. After a brief incubation, the reaction mixture is transferred to a corresponding, pre-warmed Amplification Microwell which is sealed to prevent contamination and then incubated in one of the two thermally-controlled fluorescent readers. The presence or absence of N. gonorrhoeae DNA is determined by calculating the peak fluorescence (Maximum Relative Fluorescent Units (MaxRFU)) over the course of the amplification process and by comparing this measurement to a predetermined threshold value.
In addition to the fluorescent probe used to detect amplified N. gonorrhoeae target DNA, a second fluorescently-labeled oligonucleotide is incorporated in each reaction. The Extraction Control (EC) oligonucleotide is labeled with a different dye than that used for detection of the N. gonorrhoeae-specific target and is used to confirm the validity of the extraction process. The EC is dried in the Extraction Tubes and is re-hydrated upon addition of the specimen and extraction reagents. At the end of the extraction process, the EC fluorescence is monitored by the BD Viper instrument and an automated algorithm is applied to both the EC and N. gonorrhoeae-specific signals to report specimen results as positive, negative, or EC failure.
M. Performance Characteristics (if/when applicable):
1. Analytical performance:
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a. Precision/Reproducibility:
Reproducibility of the BD Viper System using the BD ProbeTec GC Q⁺ Assay was evaluated at three clinical sites on one BD Viper System per site. A panel of simulated specimens was tested that comprised CT and GC organisms seeded into swab diluent for the BD ProbeTec GC Q⁺ Assay. Un-inoculated swab diluent for the BD ProbeTec GC Q⁺ Assay was used for the GC negative samples. Nine replicates of each panel member were tested every day for five days on each BD Viper System. The data are summarized in the following table.
Summary of Reproducibility Data on the BD Viper System for the GC Q⁺ Assay
| | | | | | | Within Run | | Between Runs Within Site | | Between Site | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Specimen Type | CT EB's/mL | GC Cells/mL | % Correct | 95% CI | MaxRFU Mean | SD | %CV | SD | %CV | SD | %CV |
| Endocervical / Urethral | 0 | 0 | 99.3% (134/135) | (95.9%, 100.0%) | 13.8 | 151.3 | 1096.3 | 0.0 | 0.0 | 0.6 | 4.3 |
| | 30 | 0 | 98.5% (133/135) | (94.8%, 99.8%) | 28.1 | 220.7 | 785.3 | 0.0 | 0.0 | 33.8 | 120.3 |
| | 0 | 100 | 100.0% (135/135) | (97.3%, 100.0%) | 1859.5 | 94.1 | 5.1 | 0.0 | 0.0 | 19.2 | 1.0 |
| | 30 | 250 | 100.0% (135/135) | (97.3%, 100.0%) | 1847.3 | 117.6 | 6.4 | 0.0 | 0.0 | 25.9 | 1.4 |
| | 75 | 100 | 100.0% (135/135) | (97.3%, 100.0%) | 1855.9 | 119.4 | 6.4 | 0.0 | 0.0 | 42.2 | 2.3 |
| Urine / Vaginal | 0 | 0 | 99.3% (134/135) | (95.9%, 100.0%) | 15.7 | 162.3 | 1031.1 | 0.0 | 0.0 | 0.0 | 0.0 |
| | 30 | 0 | 100.0% (135/135) | (97.3%, 100.0%) | 1.1 | 3.1 | 295.8 | 0.7 | 69.7 | 0.5 | 48.3 |
| | 0 | 100 | 100.0% (135/135) | (97.3%, 100.0%) | 1899.0 | 86.1 | 4.5 | 22.8 | 1.2 | 0.0 | 0.0 |
| | 30 | 250 | 100.0% (135/135) | (97.3%, 100.0%) | 1884.2 | 94.0 | 5.0 | 13.8 | 0.7 | 0.0 | 0.0 |
| | 75 | 100 | 100.0% (135/135) | (97.3%, 100.0%) | 1867.2 | 87.7 | 4.7 | 0.0 | 0.0 | 19.2 | 1.0 |
A second study was conducted internally to characterize the reproducibility of test results (i.e., proportion positive or negative) at target levels below the analytical Limit of Detection (LoD) of the BD ProbeTec GC Q⁺ Assay. A panel of simulated specimens was tested that comprised GC and CT organisms seeded into Q⁺ swab diluent at two different levels each of which was below the respective analytical LoD for the organisms (1:10, 1:100). These levels were selected to fall within the dynamic range of the analytical LOD curve of the assay. Fifteen replicates of each panel member were tested every day for five days across three BD Viper Systems. The data are summarized in the table below.
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Characterization of System Reproducibility at Target Levels below the Analytical Limit of Detection for the GC Q⁺ Assay
| Specimen | Dilution of Analytical LOD | % Positive | 95% CI (Positive) | Max RFU Mean (Positive) | % Negative | 95% CI (Negative) | Max RFU Mean (Negative) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Endocervical/Urethral | 1:10 | 92.9 (209/225) | (88.7, 95.9) | 1324.6 | 7.1 (16/225) | (4.1, 11.3) | 41.4 |
| Endocervical/Urethral | 1:100 | 30.7 (69/225) | (24.7, 37.1) | 835.9 | 69.3 (156/225) | (62.9, 75.3) | 7.2 |
| Urine/Vaginal | 1:10 | 90.7 (204/225) | (86.1, 94.1) | 1165.9 | 9.3 (21/225) | (5.9, 13.9) | 34.2 |
| Urine/Vaginal | 1:100 | 22.7 (51/225) | (17.4, 28.7) | 872.7 | 77.3 (174/225) | (71.3, 82.6) | 7.8 |
b. Linearity/assay reportable range: NA
c. Traceability, Stability, Expected values (controls, calibrators, or methods): The recommended Positive, Negative and Internal Control material were tested a sufficient number of times with acceptable results on all testing days.
d. Detection limit: Endocervical swabs and vaginal swabs were used for LoD studies because these swabs contain higher concentration of protein, mucous, and cellular debris and are considered "worst case". Urethral swabs were not tested for LoD studies.
Endocervical swabs pool - Minipool of 72 individual swab specimens in diluent showing GC negative results was divided into 6 for spiking with strain 19424 at 5 different target levels and 1 negative target level (unspiked).
Vaginal swabs pool - Minipool of 12 individual swab specimens in diluent showing GC negative results was divided into 6 for spiking with strain 19424 at 5 different target levels and 1 negative target level (unspiked).
Urine: Male and female urine specimens screened separately and equal volumes of negative specimens from male and female were pooled and were divided into 6 for spiking with strain 19424 at 5 different target levels and 1 negative target level (unspiked).
The Limits of Detection (LoDs) for the GC Q⁺ Assay with Neisseria gonorrhoeae strain ATCC 19424 in urine and swab specimens when extracted on the BD Viper System were determined to be < 50 cells per mL for neat and Q⁺ UPT urine and < 100 GC cells per mL for expressed vaginal and endocervical swab specimens.
The GC Q⁺ Assay on the BD Viper System in extracted mode was able to detect 17 GC strains (ATCC 19424, 27628, 27629, 27630, 27632, 27633, 27631, 21823, 51803, 23051, 31407, 31953, 35201, 31397, 31151, 43785, 51804) with ≥ 95% proportion positive at a concentration of 50 cells per mL in CT/GC Q⁺ Swab Diluent.
e. Analytical specificity:
1. Cross Reactivity: DNA from 141 organisms listed in the following table was extracted
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on the BD Viper System and tested with the BD ProbeTec GC Q $^{\mathrm{x}}$ Amplified DNA Assay. All potential cross-reactive species were tested at $>1 \times 10^{8}$ cells/mL except where noted. Two $N$ . cinerea and two $N$ . lactamica strains were shown to cross-react in the GC Q $^{\mathrm{x}}$ assay.
Potential Cross-reacting Microorganisms
| Acinetobacter calcoaceticus | Enterococcus faecium | Peptostreptococcus asaccharolyticus | Neisseria elongata subsp. glycolytica |
| --- | --- | --- | --- |
| Acinetobacter lwoffii | Epstein Barr Virus*** | Peptostreptococcus productus | Neisseria elongata subsp. nitroreduscens (2) |
| Actinomyces israelii | Escherichia coli | Plesiomonas shigelloides | Neisseria elongata |
| Adenovirus*** | Flavobacterium meningosepticum | Propionibacterium acnes | Neisseria flava (4) |
| Aeromonas hydrophilia | Gardnerella vaginalis | Providencia stuartii | Neisseria flavescens (4) |
| Alcaligenes faecalis* | Gemella haemolysans | Pseudomonas aeruginosa | Neisseria lactamica (7) |
| Bacillus subtilis* | Haemophilus influenzae | Salmonella minnesota | Neisseria meningitidis (12) |
| Bacteroides fragilis | Herpes Simplex Virus ** | Salmonella typhimurium | Neisseria mucosa (5) |
| Candida albicans* | Human papillomavirus (16 and 18)*** | Staphylococcus aureus | Neisseria perflava (8) |
| Candida glabrata* | Kingella kingae | Staphylococcus epidermidis | Neisseria polysaccharea (2) |
| Candida tropicalis* | Klebsiella pneumoniae | Streptococcus agalactiae | Neisseria sicca (5) |
| Chlamydia trachomatis | Lactobacillus acidophilus* | Streptococcus mitis | Neisseria subflava (15) |
| Chlamydia pneumoniae*** | Lactobacillus brevis | Streptococcus mutans | Neisseria weaverii (3) |
| Chlamydia psittaci* | Lactobacillus jensenii* | Streptococcus pneumoniae* | |
| Citrobacter freundii | Listeria monocytogenes | Streptococcus pyogenes | |
| Clostridium perfringens | Mobiluncus mulieris | Streptomyces griseus** | |
| Corynebacterium renale | Moraxella lacunata* | Trichomonas vaginalis** | |
| Cryptococcus neoformans* | Moraxella osloensis | Veillonella parvula | |
| | | | |
Cytomegalovirus Morganella Vibrio
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| ** | morganii | parahaemolyticus |
| --- | --- | --- |
| Edwardsiella tarda | Mycobacterium gordonae | Yersinia enterocolitica |
| Enterobacter cloacae | Mycobacterium smegmatis | Branhamella catarrhalis (5) |
| Enterococcus faecalis | Peptostreptococcus anaerobius | Neisseria cinerea (2) |
(n) number of strains tested in the BD ProbeTec GC Qx Assay
* Tested at > 1x10⁷ cells or EB/mL; **Tested at > 1x10⁶ cells or viral particles per mL; ***Tested at > 1x10⁶ genomic equivalents per mL; *** tested at > 1x10⁵ TCID₅₀/mL
2. Interference: The performance of the BD ProbeTec GC Qx Assay on the BD Viper System in extracted mode was evaluated in the presence of potential interfering substances which may be encountered in swab and/or urine specimens. Potential interfering substances were spiked into UPT urine and vaginal swab specimen matrices in both the presence and the absence of GC organisms (150 GC cells/mL in urine matrix and 300 GC cells/mL in swab matrix). Results are summarized in the following table.
GC Qx Interfering Substances
| Interpretation | Swab | Urine |
| --- | --- | --- |
| No Interference Observed | Blood (≤60%)
Seminal Fluid
Mucus
Over The Counter vaginal products and contraceptives
Hemorrhoidal cream
Prescription vaginal treatments
Leukocytes (1x10⁶ cells/mL)
1x10⁶ EB/mL Chlamydia trachomatis | Blood (≤1%)
Seminal fluid
Mucus
Antibiotics
Analgesics
Over The Counter deodorant sprays and powders
Hormones
Leukocytes
Albumin <1 mg/mL
Glucose
Acidic urine (pH 4.0)
Alkaline urine (pH 9.0)
Bilirubin
1x10⁶ EB/mL Chlamydia trachomatis
Organisms associated with Urinary Tract Infections |
| May cause extraction control (EC) failures | Blood (>60%) | Not applicable |
f. Assay cut-off: NA
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g. Cross Contamination and Carryover
An internal study was conducted to evaluate the risk of producing a false positive result in either the same run on the BD Viper System in extracted mode (within run cross-contamination) or in a subsequent run (between run carryover). Testing was conducted using negative and positive samples on three BD Viper Systems. Negative samples consisted of CT/GC Q⁴ Swab Diluent. Positive samples consisted of a representative analyte (10⁵ CT EB/mL) spiked into CT/GC Q⁴ Swab Diluent. The overall rate of cross-contamination (i.e., with alternating columns of positive and negative samples and a prevalence of 50%) was 0.41% (9/2208). The overall rate of carryover contamination (i.e., carryover between successive runs when the prevalence was 50% in the previous run) was 0.36% (8/2208). Cross-contamination and carryover rates across the three BD Viper Systems are summarized in the table.
Cross Contamination and Carryover Contamination
| Assay Dispense Mode Selected | BD Viper System | Cross-Contamination | | | Carryover Contamination | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | | n | Positive Results | Percent Positive | n | Positive Results | Percent Positive |
| Dual Assay | 1 | 736 | 5 | 0.68 | 736 | 1 | 0.14 |
| | 2 | 736 | 0 | 0.00 | 736 | 3 | 0.41 |
| | 3 | 736 | 4 | 0.54 | 736 | 4 | 0.54 |
| | Overall | 2208 | 9 | 0.41 | 2208 | 8 | 0.36 |
| Single Assay | 1 | 190 | 0 | 0.00 | 186 | 0 | 0.00 |
| | 2 | 188 | 1 | 0.53 | 186 | 1 | 0.54 |
| | 3 | 188 | 0 | 0.00 | 186 | 0 | 0.00 |
| | Overall | 566 | 1 | 0.18 | 568 | 1 | 0.18 |
2. Comparison studies:
a. Method comparison with predicate method: See below under Performance Characteristics
b. Matrix comparison: NA
3. Clinical studies:
a. Clinical Sensitivity: NA
b. Clinical specificity: NA
Performance Characteristics
Clinician-collected endocervical and male urethral swab specimens, patient-collected vaginal swab specimens (in a clinical setting), and male and female Q⁵ UPT and neat
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urine specimens were collected from 1059 female subjects and 479 male subjects attending OB/GYN, sexually transmitted disease (STD) and family planning clinics at seven geographically diverse clinical sites in North America. Subjects were classified as symptomatic if they reported symptoms such as dysuria, urethral discharge, coital pain/difficulty/bleeding, testicular or scrotum pain/swelling, abnormal vaginal discharge, or pelvic/uterine/adnexal pain. Subjects were classified as asymptomatic if they did not report symptoms. Sixty five female subjects and 7 male subjects were excluded from the data analysis due to age requirement violations, antibiotic treatment in the last 21 days, opting to withdraw from the study after initially consenting, failure to obtain paired swab and urine specimens, urine quantity less than 20 mL, or transport and storage errors related to specimen collection. Therefore, the final data analysis included 994 compliant female subjects and 472 compliant male subjects.
Five specimens were collected from each of the 994 eligible female subjects. A urine specimen was collected and split into Qⁱ UPT, neat urine and the two reference urine specimen collection devices followed by a vaginal swab specimen and three randomized endocervical swab specimens. Up to four specimens were collected from each of the 472 eligible male subjects. Up to three randomized urethral swab specimens were collected followed by a urine specimen that was split into Qⁱ UPT, neat urine and the two reference urine specimen collection devices. BD ProbeTec GC Qⁱ assay results were generated from the Qⁱ UPT and neat urine specimens, the vaginal swab specimen, one endocervical swab specimen and one male urethral swab specimen. The remaining two endocervical swab specimens, up to two male urethral swab specimens, and the two reference urine specimens for each male and female subject were tested using two reference methods: the BD ProbeTec ET GC/AC assay and another commercially available NAAT (Nucleic Acid Amplification Test). Specimen testing was conducted either at the site of collection or at a designated BD Viper testing site.
All performance calculations were based on the total number of BD ProbeTec GC Qⁱ assays results for endocervical, vaginal and male urethral swab specimens, and male and female Qⁱ UPT and neat urine specimens compared to a patient infected status (PIS) algorithm for each gender. In the algorithm, the designation of a subject as being infected with GC or not was based on endocervical swab and urine specimen results from the commercially available BD ProbeTec ET GC/AC assay and the other commercially available NAAT. Subjects were considered infected with GC if two of the four endocervical swab and urine specimens (or two of the three or four urethral swab and urine specimens) tested positive in the BD ProbeTec ET GC/AC assay and the other reference NAAT (one specimen testing positive in each NAAT). Subjects were considered non-infected if less than two reference NAAT results were positive. A total of 5387 BD ProbeTec GC Qⁱ assay results was used to calculate sensitivity and specificity. Sensitivity and specificity by specimen type and symptomatic status are presented in the table below.
Performance of the assay with endocervical swabs, patient collected vaginal swabs specimens (in a clinical setting), female UPT and neat urine was assessed in the clinical study. Separate performance was calculated for specimens collected from pregnant females. Sensitivity compared to patient infected status for FS, FV, FNU, and FUPT was 100% (3/3). In each case, specificity was 100% (24/24) for FS, FV, FNU, and FUPT separately.
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GC Q $^x$ Assay Performance Compared to Patient Infected Status (by specimen type and symptomatic status)
| Specimen Type | Symptomatic | N | Sensitivity | 95% C.I. | Specificity | 95% C.I. | PPV% | NPV% | Error Initial/Final |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| FS | N | 450 | 96.3% (26/27) | (81.0% - 99.9%) | 99.5% (421/423) | (98.3% - 99.9%) | 92.9 | 99.8 | 3/0 |
| | Y | 542 | 100.0% (38/38) | (90.7% - 100.0%) | 99.8% (503/504) | (98.9% - 100.0%) | 97.4 | 100.0 | 2/2 |
| | Total | 992 | 98.5% (64/65) | (91.7% - 100.0%) | 99.7% (924/927) | (99.1% - 99.9%) | 95.5 | 99.9 | 5/2 |
| FV | N | 449 | 100.0% (27/27) | (87.2% - 100.0%) | 98.6% (416/422) | (96.9% - 99.5%) | 81.8 | 100.0 | 0/0 |
| | Y | 544 | 100.0% (38/38) | (90.7% - 100.0%) | 99.6% (504/506) | (98.6% - 100.0%) | 95.0 | 100.0 | 0/0 |
| | Total | 993 | 100.0% (65/65) | (94.5% - 100.0%) | 99.1% (920/928) | (98.3% - 99.6%) | 89.0 | 100.0 | 0/0 |
| FN | N | 450 | 96.3% (26/27) | (81.0% - 99.9%) | 99.3% (420/423) | (97.9% - 99.9%) | 89.7 | 99.8 | 0/0 |
| | Y | 543 | 97.4% (37/38) | (86.2% - 99.9%) | 99.6% (503/505) | (98.6% - 100.0%) | 94.9 | 99.8 | 0/0 |
| | Total | 993 | 96.9% (63/65) | (89.3% - 99.6%) | 99.5% (923/928) | (98.7% - 99.8%) | 92.6 | 99.8 | 0/0 |
| FUPT | N | 450 | 100.0% (27/27) | (87.2% - 100.0%) | 99.5% (421/423) | (98.3% - 99.9%) | 93.1 | 100.0 | 0/0 |
| | Y | 543 | 97.4% (37/38) | (86.2% - 99.9%) | 99.8% (504/505) | (98.9% - 100.0%) | 97.4 | 99.8 | 0/0 |
| | Total | 993 | 98.5% (64/65) | (91.7% - 100.0%) | 99.7% (925/928) | (99.1% - 99.9%) | 95.5 | 99.9 | 0/0 |
| MS | N | 215 | 100.0% (7/7) | (59.0% - 100.0%) | 100.0% (208/208) | (98.2% - 100.0%) | 100.0 | 100.0 | 0/0 |
| | Y | 257 | 100.0% (100/100) | (96.4% - 100.0%) | 98.7% (155/157) | (95.5% - 99.8%) | 98.0 | 100.0 | 1/0 |
| | Total | 472 | 100.0% (107/107) | (96.6% - 100.0%) | 99.5% (363/365) | (98.0% - 99.9%) | 98.2 | 100.0 | 1/0 |
| MN | N | 215 | 100.0% (7/7) | (59.0% - 100.0%) | 100.0% (208/208) | (98.2% - 100.0%) | 100.0 | 100.0 | 0/0 |
| | Y | 257 | 100.0% (100/100) | (96.4% - 100.0%) | 98.1% (154/157) | (94.5% - 99.6%) | 97.1 | 100.0 | 0/0 |
| | Total | 472 | 100.0% (107/107) | (96.6% - 100.0%) | 99.2% (362/365) | (97.6% - 99.8%) | 97.3 | 100.0 | 0/0 |
| MUPT | N | 215 | 100.0% (7/7) | (59.0% - 100.0%) | 99.5% (207/208) | (97.4% - 100.0%) | 87.5 | 100.0 | 0/0 |
| | Y | 257 | 100.0% (100/100) | (96.4% - 100.0%) | 98.7% (155/157) | (95.5% - 99.8%) | 98.0 | 100.0 | 0/0 |
| | Total | 472 | 100.0% (107/107) | (96.6% - 100.0%) | 99.2% (362/365) | (97.6% - 99.8%) | 97.3 | 100.0 | 0/0 |
| Total | | 5387 | 99.3% (577/581) | (98.2% - 99.8%) | 99.4% (4779/4806) | (99.2% - 99.6%) | 95.5 | 99.9 | 6/2 |
{11}
GC Q $^{\text{X}}$ Assay Performance Compared to Patient Infected Status (by clinical site)
| Specimen Type | Site | Prevalence | n | Sensitivity | 95% C.I. | Specificity | 95% C.I. | # CT (+) and GC (+) | PPV% | NPV% |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| FS1 | 1 | 8.4% | 155 | 100.0% (13/13) | (75.3% - 100.0%) | 99.3% (141/142) | (96.1% - 100.0%) | 5 | 92.9% | 100.0% |
| | 2 | 10.4% | 154 | 93.8% (15/16) | (69.8% - 99.8%) | 99.3% (137/138) | (96.0% - 100.0%) | 6 | 93.7% | 99.3% |
| | 3 | 6.8% | 73 | 100.0% (5/5) | (47.8% - 100.0%) | 98.5% (67/68) | (92.1% - 100.0%) | 2 | 83.3% | 100.0% |
| | 4 | 19.0% | 105 | 100.0% (20/20) | (83.2% - 100.0%) | 100.0% (85/85) | (95.8% - 100.0%) | 6 | 100.0% | 100.0% |
| | 5 | 1.4% | 70 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (69/69) | (94.8% - 100.0%) | 0 | 100.0% | 100.0% |
| | 6 | 2.2% | 365 | 100.0% (8/8) | (63.1% - 100.0%) | 100.0% (357/357) | (99.0% - 100.0%) | 3 | 100.0% | 100.0% |
| | 7 | 2.9% | 70 | 100.0% (2/2) | (15.8% - 100.0%) | 100.0% (68/68) | (94.7% - 100.0%) | 0 | 100.0% | 100.0% |
| FV2 | 1 | 8.4% | 155 | 100.0% (13/13) | (75.3% - 100.0%) | 99.3% (141/142) | (96.1% - 100.0%) | 5 | 92.9% | 100.0% |
| | 2 | 10.3% | 155 | 100.0% (16/16) | (79.4% - 100.0%) | 97.1% (135/139) | (92.8% - 99.2%) | 6 | 80.0% | 100.0% |
| | 3 | 6.8% | 73 | 100.0% (5/5) | (47.8% - 100.0%) | 100.0% (68/68) | (94.7% - 100.0%) | 2 | 100.0% | 100.0% |
| | 4 | 19.0% | 105 | 100.0% (20/20) | (83.2% - 100.0%) | 97.6% (83/85) | (91.8% - 99.7%) | 6 | 90.9% | 100.0% |
| | 5 | 1.4% | 70 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (69/69) | (94.8% - 100.0%) | 0 | 100.0% | 100.0% |
| | 6 | 2.2% | 365 | 100.0% (8/8) | (63.1% - 100.0%) | 99.7% (356/357) | (98.4% - 100.0%) | 3 | 88.9% | 100.0% |
| | 7 | 2.9% | 70 | 100.0% (2/2) | (15.8% - 100.0%) | 100.0% (68/68) | (94.7% - 100.0%) | 0 | 100.0% | 100.0% |
| FNU3 | 1 | 8.4% | 155 | 100.0% (13/13) | (75.3% - 100.0%) | 98.6% (140/142) | (95.0% - 99.8%) | 5 | 86.7% | 100.0% |
| | 2 | 10.3% | 155 | 93.8% (15/16) | (69.8% - 99.8%) | 97.8% (136/139) | (93.8% - 99.6%) | 6 | 83.3% | 99.3% |
| | 3 | 6.8% | 73 | 100.0% (5/5) | (47.8% - 100.0%) | 100.0% (68/68) | (94.7% - 100.0%) | 2 | 100.0% | 100.0% |
| | 4 | 19.2% | 104 | 100.0% (20/20) | (83.2% - 100.0%) | 100.0% (84/84) | (95.7% - 100.0%) | 6 | 100.0% | 100.0% |
| | 5 | 1.4% | 70 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (69/69) | (94.8% - 100.0%) | 0 | 100.0% | 100.0% |
{12}
| Specimen Type | Site | Prevalence | n | Sensitivity | 95% C.I. | Specificity | 95% C.I. | # CT (+) and GC (+) | PPV% | NPV% |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | 6 | 2.2% | 366 | 100.0% (8/8) | (63.1% - 100.0%) | 100.0% (358/358) | (99.0% - 100.0%) | 3 | 100.0% | 100.0% |
| | 7 | 2.9% | 70 | 50.0% (1/2) | (1.3% - 98.7%) | 100.0% (68/68) | (94.7% - 100.0%) | 0 | 100.0% | 98.6% |
| FUPT4 | 1 | 8.4% | 155 | 100.0% (13/13) | (75.3% - 100.0%) | 99.3% (141/142) | (96.1% - 100.0%) | 5 | 92.9% | 100.0% |
| | 2 | 10.3% | 155 | 93.8% (15/16) | (69.8% - 99.8%) | 99.3% (138/139) | (96.1% - 100.0%) | 6 | 93.8% | 99.3% |
| | 3 | 6.8% | 73 | 100.0% (5/5) | (47.8% - 100.0%) | 100.0% (68/68) | (94.7% - 100.0%) | 2 | 100.0% | 100.0% |
| | 4 | 19.2% | 104 | 100.0% (20/20) | (83.2% - 100.0%) | 98.8% (83/84) | (93.5% - 100.0%) | 6 | 95.2% | 100.0% |
| | 5 | 1.4% | 70 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (69/69) | (94.8% - 100.0%) | 0 | 100.0% | 100.0% |
| | 6 | 2.2% | 366 | 100.0% (8/8) | (63.1% - 100.0%) | 100.0% (358/358) | (99.0% - 100.0%) | 3 | 100.0% | 100.0% |
| | 7 | 2.9% | 70 | 100.0% (2/2) | (15.8% - 100.0%) | 100.0% (68/68) | (94.7% - 100.0%) | 0 | 100.0% | 100.0% |
| MS5 | 1 | 15.3% | 203 | 100.0% (31/31) | (88.8% - 100.0%) | 100.0% (172/172) | (97.9% - 100.0%) | 9 | 100.0% | 100.0% |
| | 2 | 42.1% | 76 | 100.0% (32/32) | (89.1% - 100.0%) | 95.5% (42/44) | (84.5% - 99.4%) | 10 | 94.1% | 100.0% |
| | 4 | 33.7% | 101 | 100.0% (34/34) | (89.7% - 100.0%) | 100.0% (67/67) | (94.6% - 100.0%) | 11 | 100.0% | 100.0% |
| | 5 | 12.7% | 71 | 100.0% (9/9) | (66.4% - 100.0%) | 100.0% (62/62) | (94.2% - 100.0%) | 3 | 100.0% | 100.0% |
| | 7 | 4.8% | 21 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (20/20) | (83.2% - 100.0%) | 0 | 100.0% | 100.0% |
| MNU6 | 1 | 15.3% | 203 | 100.0% (31/31) | (88.8% - 100.0%) | 100.0% (172/172) | (97.9% - 100.0%) | 9 | 100.0% | 100.0% |
| | 2 | 42.1% | 76 | 100.0% (32/32) | (89.1% - 100.0%) | 95.5% (42/44) | (84.5% - 99.4%) | 10 | 94.1% | 100.0% |
| | 4 | 33.7% | 101 | 100.0% (34/34) | (89.7% - 100.0%) | 98.5% (66/67) | (92.0% - 100.0%) | 11 | 97.1% | 100.0% |
| | 5 | 12.7% | 71 | 100.0% (9/9) | (66.4% - 100.0%) | 100.0% (62/62) | (94.2% - 100.0%) | 3 | 100.0% | 100.0% |
| | 7 | 4.8% | 21 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (20/20) | (83.2% - 100.0%) | 0 | 100.0% | 100.0% |
4 22 of the 65 FUPT PIS positive subjects were co-infected with CT. BD ProbeTec GC Q+ Amplified DNA Assay sensitivity was 95.5% (21/22).
5 33 of the 107 MS PIS positive subjects were co-infected with CT. BD ProbeTec GC Q+ Amplified DNA Assay sensitivity was 100% (33/33).
6 33 of the 107 MNU PIS positive subjects were co-infected with CT. BD ProbeTec GC Q+ Amplified DNA Assay sensitivity was 100% (33/33).
{13}
| Specimen Type | Site | Prevalence | n | Sensitivity | 95% C.I. | Specificity | 95% C.I. | # CT (+) and GC (+) | PPV% | NPV% |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| MUPT^{7} | 1 | 15.3% | 203 | 100.0% (31/31) | (88.8% - 100.0%) | 99.4% (171/172) | (96.8% - 100.0%) | 9 | 96.9% | 100.0% |
| | 2 | 42.1% | 76 | 100.0% (32/32) | (89.1% - 100.0%) | 97.7% (43/44) | (88.0% - 99.9%) | 10 | 97.0% | 100.0% |
| | 4 | 33.7% | 101 | 100.0% (34/34) | (89.7% - 100.0%) | 100.0% (67/67) | (94.6% - 100.0%) | 11 | 100.0% | 100.0% |
| | 5 | 12.7% | 71 | 100.0% (9/9) | (66.4% - 100.0%) | 98.4% (61/62) | (91.3% - 100.0%) | 3 | 90.0% | 100.0% |
| | 7 | 4.8% | 21 | 100.0% (1/1) | (2.5% - 100.0%) | 100.0% (20/20) | (83.2% - 100.0%) | 0 | 100.0% | 100.0% |
1. 22 of the 65 FS PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 100% (22/22).
2. 22 of the 65 FV PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 100% (22/22).
3. 22 of the 65 FNU PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 95.5% (21/22).
4. 22 of the 65 FUPT PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 95.5% (21/22).
5. 33 of the 107 MS PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 100% (33/33).
6. 33 of the 107 MNU PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 100% (33/33).
7. 33 of the 107 MUPT PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 100% (33/33).
7 33 of the 107 MUPT PIS positive subjects were co-infected with CT. BD ProbeTec GC Qᵃ Amplified DNA Assay sensitivity was 100% (33/33).
{14}
Analysis of GC Positive/Negative Specimens from Female Subjects Based on Patient Infected Status
| | NAAT 1 | | NAAT 2 | | BD ProbeTec GC Q® Amplified DNA Assay | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| PIS GC | Endocervical Swab | Urine | Endocervical Swab | Urine | Q® Endocervical Swab | Q® Vaginal Swab | Neat Urine | Q® UPT Urine | Symptomatic Status | | |
| | | | | | | | | | A | S | Total |
| + | - | + | + | + | - | + | + | + | 1 | 0 | 1 |
| | + | - | + | - | + | + | - | - | 0 | 1 | 1 |
| | + | - | + | - | + | + | + | + | 3 | 0 | 3 |
| | + | - | + | + | + | + | + | + | 1 | 1 | 2 |
| | + | + | + | - | + | + | + | + | 2 | 1 | 3 |
| | + | + | + | + | + | + | - | + | 1 | 0 | 1 |
| | + | + | + | + | + | + | + | + | 19 | 35 | 54 |
| Total PIS Positive | | | | | | | | | 27 | 38 | 65 |
| - | NA | - | - | - | - | - | - | - | 12 | 2 | 14 |
| | - | NA | E | - | - | - | NA | NA | 0 | 1 | 1 |
| | - | NA | - | - | - | - | - | - | 1 | 1 | 2 |
| | - | I | - | - | - | - | - | - | 5 | 1 | 6 |
| | - | - | NA | - | - | - | - | - | 1 | 2 | 3 |
| | - | - | E | - | - | - | - | - | 1 | 0 | 1 |
| | - | - | - | - | ET | - | - | - | 0 | 1 | 1 |
| | - | - | - | - | LE | - | - | - | 0 | 1 | 1 |
| | - | - | - | - | - | NA | - | - | 1 | 0 | 1 |
| | - | - | - | - | - | - | - | - | 390 | 484 | 874 |
| | - | - | - | - | - | - | - | + | 0 | 1 | 1 |
| | - | - | - | - | - | - | + | - | 1 | 1 | 2 |
| | - | - | - | - | - | + | - | - | 4 | 1 | 5 |
| | - | - | - | - | - | + | + | - | 0 | 1 | 1 |
| | - | - | - | - | - | + | + | + | 1 | 0 | 1 |
| | - | - | - | - | + | - | - | - | 0 | 1 | 1 |
| | - | - | + | - | - | - | - | - | 1 | 3 | 4 |
| | - | - | + | - | + | - | - | - | 1 | 0 | 1 |
| | - | + | - | - | - | - | - | - | 1 | 2 | 3 |
| | + | - | - | - | - | - | - | - | 2 | 3 | 5 |
| | + | + | - | - | + | + | + | + | 1 | 0 | 1 |
| Total PIS Negative | | | | | | | | | 423 | 506 | 929 |
I Indeterminate
E Error
LE Liquid Level Error
ET Extraction Transfer Error
{15}
Analysis of GC Positive/Negative Specimens from Male Subjects Based on Patient Infected Status
| | NAAT 1 | | NAAT 2 | | BD ProbeTec GC Q^{4}Amplified DNA Assay | | | Symptomatic Status | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| PIS GC | Urethral Swab | Urine | Urethral Swab | Urine | Q^{x}Urethral Swab | Neat Urine | Q^{x}UPT Urine | A | S | Total |
| + | NA | + | + | + | + | + | + | 0 | 6 | 6 |
| | + | + | NA | + | + | + | + | 0 | 13 | 13 |
| | + | + | + | + | + | + | + | 7 | 81 | 88 |
| Total PIS Positive | | | | | | | | 7 | 100 | 107 |
| - | NA | - | - | - | - | - | - | 3 | 11 | 14 |
| | NA | - | + | - | - | - | - | 1 | 0 | 1 |
| | NA | - | + | + | + | + | + | 0 | 1 | 1 |
| | NA | + | - | - | - | - | - | 0 | 1 | 1 |
| | - | I | NA | - | - | - | - | 1 | 0 | 1 |
| | - | I | - | - | - | - | - | 4 | 1 | 5 |
| | - | - | NA | - | - | - | - | 13 | 11 | 24 |
| | - | - | E | - | - | - | - | 2 | 0 | 2 |
| | - | - | - | E | - | - | - | 0 | 1 | 1 |
| | - | - | - | - | - | - | - | 180 | 124 | 304 |
| | - | - | - | - | - | - | + | 1 | 1 | 2 |
| | - | - | - | - | - | + | - | 0 | 1 | 1 |
| | - | - | - | + | - | - | - | 2 | 1 | 3 |
| | - | - | + | - | - | - | - | 1 | 1 | 2 |
| | - | - | + | + | + | + | - | 0 | 1 | 1 |
| | + | - | - | - | - | - | - | 0 | 1 | 1 |
| | + | + | NA | - | - | - | - | 0 | 1 | 1 |
| Total PIS Negative | | | | | | | | 208 | 157 | 365 |
4. Clinical cut-off: Clinical cut-off was estimated by evaluating GCQ assay results obtained from a total of 696 unique subjects for a total of 4878 assay results. This dataset included both the initial and repeat assay results: specimens were tested and then retested, and both results were included in the analysis in order to generate a larger data pool for use in training the algorithm. The optimal cutoff for the GCQ Assay was located between 50 and 250 MaxRFU based on the analysis of this dataset. When evaluating assay sensitivity and specificity over this range of values across all specimen types, the assay sensitivity and specificity were relatively constant at approximately 92 and 99%, respectively. In order to guard against false positive results (protect specificity), the preliminary cutoff was set at 125 MaxRFU. These preliminary cutoff values were incorporated into the version of algorithm software that was utilized in the Cutoff Trial by the BD Viper System operating in extracted mode.
5. Expected values/Reference range:
A. Prevalence: The prevalence of positive N. gonorrhoeae specimens in patient
{16}
populations depends upon: clinic type, age, risk factors, gender, and test method. The prevalence observed with the GC Q $^{\text{x}}$ Amplified DNA Assay during a multi-center clinical trial ranged from $1.4\%$ to $19.1\%$ for female specimens and $4.8\%$ to $42.1\%$ for male specimens.
B. Positive and Negative Predictive Value: Hypothetical positive and negative predictive values (PPV & NPV) for the GC Q $^{\text{x}}$ Assay are shown in the following table. These calculations are based on hypothetical prevalence and overall sensitivity and specificity (compared to the patient infected status) of $99.3\%$ and $99.4\%$ , respectively. In addition, PPV and NPV based on actual prevalence, sensitivity and specificity are shown in the tables under performance characteristics section (See “GC Q $^{\text{x}}$ Assay Performance Compared to Patient Infected Status (by specimen type and symptomatic status)” and “GC Q $^{\text{x}}$ Assay Performance Compared to Patient Infected Status (by clinical site).” PPV was calculated using: (Sensitivity * Prevalence) / (Sensitivity*Prevalence + (1 - Specificity) * (1 - Prevalence)). NPV was calculated using: (Specificity * (1 - Prevalence)/ (1-Sensitivity) * Prevalence + Specificity * (1-Prevalence)).
# GC Hypothetical Positive and Negative Predictive Values Compared to Patient Infected Status
| Prevalence (%) | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) |
| --- | --- | --- | --- | --- |
| 2 | 99.3 | 99.4 | 78.3 | 100.0 |
| 5 | 99.3 | 99.4 | 90.3 | 100.0 |
| 10 | 99.3 | 99.4 | 95.2 | 99.9 |
| 20 | 99.3 | 99.4 | 97.8 | 99.8 |
| 30 | 99.3 | 99.4 | 98.7 | 99.7 |
| 40 | 99.3 | 99.4 | 99.2 | 99.5 |
| 50 | 99.3 | 99.4 | 99.4 | 99.3 |
# N. Instrument:
BD Viper™ System in extracted mode with the addition of the CTQ and GCQ Assays: The BD Viper System with the capability of automated nucleic acid extraction is the third generation of the BD Viper robotic platform for amplified DNA analysis. The system builds upon its predecessors, the BD Viper Instrument (K023955) and the BD Viper System (K052481).
# O. System Descriptions:
Viewing the BD Viper System from the perspective of assay workflow, the level of automation added to enable automated nucleic acid extraction on the existing BD Viper System includes the following:
(1) chemical lysis of organisms in clinical specimens,
(2) chemical extraction and purification of DNA using paramagnetic particles facilitated by employment of an extractor block containing a movable magnet assembly;
{17}
(3) elution of extracted DNA into SDA-compatible buffer; and
(4) transfer of the eluate from the extraction tube to the assay priming microwells.
Beyond these additions to the existing BD Viper System’s workflow, the following processing functions are common to both systems (extracted and non-extracted):
(5) priming microwell heat spike;
(6) transfer of sample from priming microwells to prewarmed amplification microwells located directly on the reader stage/heater;
(7) amplification microwell plate sealing and movement of the sealed amplification microwells into the fluorescent reader;
(8) amplification temperature control and fluorescent photodetection; and
(9) calculation and result interpretation.
2. Software: The FDA has reviewed applicant’s Hazard Analysis and Software development processes for the device
## P. Other Supportive Device and Instrument Information: NA
## Q. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.
## R. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
