K253756 · Roche Molecular Systems, Inc. · QEP · May 15, 2026 · Microbiology
Device Facts
Record ID
K253756
Device Name
cobas liat CT/NG nucleic acid test
Applicant
Roche Molecular Systems, Inc.
Product Code
QEP · Microbiology
Decision Date
May 15, 2026
Decision
SESE
Submission Type
Dual Track
Regulation
21 CFR 866.3393
Device Class
Class 2
Indications for Use
The cobas liat CT/NG nucleic acid test is an automated, qualitative in vitro nucleic acid diagnostic test that utilizes real-time polymerase chain reaction (PCR) for the direct detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) nucleic acid in male/female urine and vaginal swabs, all in cobas PCR Media (Roche Molecular Systems, Inc.). This test is intended as an aid in the diagnosis of urogenital infections in both symptomatic and asymptomatic individuals.
Device Story
The cobas liat CT/NG nucleic acid test is an automated, qualitative in vitro diagnostic test performed on the cobas liat analyzer. It processes biological samples (urine or vaginal swabs in cobas PCR Media) to detect Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) DNA. The system integrates sample purification, nucleic acid amplification, and real-time PCR detection within a closed, self-contained assay tube. The analyzer uses multiple processing modules and actuators to move the sample through pre-packed reagent segments, performing lysis, nucleic acid binding to magnetic particles, washing, elution, and PCR amplification. An embedded microprocessor controls all steps without user intervention. The system provides interpreted results in approximately 20 minutes. It is intended for use in clinical settings to aid in the diagnosis of urogenital infections. Healthcare providers use the output to confirm infection status, facilitating clinical decision-making and patient management.
Clinical Evidence
Multi-site, prospective clinical study (n=4852) compared cobas liat CT/NG results to a Patient Infected Status (PIS) or Composite Comparator Algorithm (CCA) using FDA-cleared NAATs. Performance evaluated across male urine, female urine, and vaginal swabs. Sensitivity for CT ranged 94.6%-98.4% and specificity 99.3%-99.9%. Sensitivity for NG ranged 91.7%-100% and specificity 99.8%-100%. Invalid rate was 0.2% after retesting.
Technological Characteristics
The system utilizes real-time PCR for nucleic acid amplification and detection. It features a closed, self-contained assay tube containing magnetic particles, lysis/wash/elution buffers, and PCR mastermix. The analyzer uses automated sample processing modules and an embedded microprocessor for thermal cycling and real-time fluorescence detection. The system is designed for point-of-care or laboratory use, requiring barcode-based specimen identification. It is a standalone system with no external connectivity requirements for basic operation.
Indications for Use
Indicated for symptomatic and asymptomatic individuals, including males and females, for the diagnosis of urogenital Chlamydia trachomatis and Neisseria gonorrhoeae infections using urine or vaginal swab specimens.
Regulatory Classification
Identification
A device to detect nucleic acids from non-viral microorganism(s) causing sexually transmitted infections and associated resistance marker(s) is an in vitro diagnostic device intended for the detection and identification of nucleic acids from non-viral microorganism(s) and their associated resistance markers in clinical specimens collected from patients suspected of sexually transmitted infections. The device is intended to aid in the diagnosis of non-viral sexually transmitted infections in conjunction with other clinical and laboratory data. These devices do not provide confirmation of antibiotic susceptibility since mechanisms of resistance may exist that are not detected by the device.
Special Controls
A device to detect nucleic acids from non-viral microorganism(s) causing sexually transmitted infections and associated resistance marker(s) must comply with the following special controls: (1) The intended use for the 21 CFR 809.10 labeling must include a detailed description of targets the device detects, the results provided to the user, the clinical indications appropriate for test use, and the specific population(s) for which the device is intended. (2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device: alternatively, the sample collection device must be cleared in a premarket submission as a part of this device. (3) The 21 CFR 809.10(b) labeling must include: (i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens; (ii) Detailed discussion of the performance characteristics of the device for all claimed specimen types based on analytical studies, including, but not limited to. Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, with-in lab precision, and reproducibility, as appropriate; (iii) Detailed descriptions of the test procedure, the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing. (iv) Limiting statements indicating that: (A)a negative test result does not preclude the possibility of infection; (B) the test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician; (C) reliable results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe procedures in any one of these steps can lead to incorrect results; and (D)if appropriate (e.g., recommended by CDC, by current well-accepted clinical guidelines, or by published peer reviewed research), that the clinical performance is inferior in a specific clinical subpopulation or for a specific claimed specimen type. (v) If the device is intended to detect antimicrobial resistance markers, limiting statements, as appropriate, indicating that: (A)negative results for claimed resistance markers do not indicate susceptibility of detected microorganisms, as resistance markers not measured by the assay or other potential mechanisms of antibiotic resistance may be present; (B) detection of resistance markers cannot be definitively linked to specific microorganisms and the source of a detected resistance marker may be an organism not detected by the assay, including colonizing flora; (C) detection of antibiotic resistance markers may not correlate with phenotypic gene expression; and (D) therapeutic failure or success cannot be determined based on the assay results, since nucleic acid may persist following appropriate antimicrobial therapy. (4) Design verification and validation must include: (i) Detailed device description documentation, including, but not limited to, methodology from obtaining sample to result, design of primer/probe sequences, rationale for target sequence selection, and computational path from collected raw data to reported result (e.g., how collected raw signals are converted into a reported result). (ii) Detailed documentation of analytical studies including but not limited to, Limit of Detection, inclusivity, cross-reactivity, microbial interference, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, with-in lab precision, and reproducibility, as appropriate. (iii) Detailed documentation and performance results from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, when determined to be appropriate by FDA, additional characterized clinical samples. The study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained from FDA accepted comparator methods. Documentation from the clinical studies must include the clinical study protocol (including a predefined statistical analysis plan) study report, testing results, and results of all statistical analyses. (iv) A detailed description of the impact of any software, including, but not limited to, software applications and hardware-based devices that incorporate software, on the device's functions.
*Classification.* Class II (special controls). The special controls for this device are:(1) The intended use for the labeling required under § 809.10 of this chapter must include a detailed description of targets the device detects, the results provided to the user, the clinical indications appropriate for test use, and the specific population(s) for which the device is intended.
(2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device; alternatively, the sample collection device must be cleared in a premarket submission as a part of this device.
(3) The labeling required under § 809.10(b) of this chapter must include:
(i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens;
(ii) Detailed discussion of the performance characteristics of the device for all claimed specimen types based on analytical studies, including Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, within lab precision, and reproducibility, as appropriate;
(iii) Detailed descriptions of the test procedure, the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing;
(iv) Limiting statements indicating that:
(A) A negative test result does not preclude the possibility of infection;
(B) The test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician;
(C) Reliable results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe proper procedures in any one of these steps can lead to incorrect results; and
(D) If appropriate (
*e.g.,* recommended by the Centers for Disease Control and Prevention, by current well-accepted clinical guidelines, or by published peer reviewed research), that the clinical performance is inferior in a specific clinical subpopulation or for a specific claimed specimen type; and(v) If the device is intended to detect antimicrobial resistance markers, limiting statements, as appropriate, indicating that:
(A) Negative results for claimed resistance markers do not indicate susceptibility of detected microorganisms, as resistance markers not measured by the assay or other potential mechanisms of antibiotic resistance may be present;
(B) Detection of resistance markers cannot be definitively linked to specific microorganisms and the source of a detected resistance marker may be an organism not detected by the assay, including colonizing flora;
(C) Detection of antibiotic resistance markers may not correlate with phenotypic gene expression; and
(D) Therapeutic failure or success cannot be determined based on the assay results, since nucleic acid may persist following appropriate antimicrobial therapy.
(4) Design verification and validation must include:
(i) Detailed device description documentation, including methodology from obtaining sample to result, design of primer/probe sequences, rationale for target sequence selection, and computational path from collected raw data to reported result (
*e.g.,* how collected raw signals are converted into a reported result).(ii) Detailed documentation of analytical studies, including, Limit of Detection, inclusivity, cross-reactivity, microbial interference, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, within lab precision, and reproducibility, as appropriate.
(iii) Detailed documentation and performance results from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, when determined to be appropriate by FDA, additional characterized clinical samples. The study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained from FDA accepted comparator methods. Documentation from the clinical studies must include the clinical study protocol (including a predefined statistical analysis plan) study report, testing results, and results of all statistical analyses.
(iv) A detailed description of the impact of any software, including software applications and hardware-based devices that incorporate software, on the device's functions.
{0}
FDA U.S. FOOD & DRUG ADMINISTRATION
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
ASSAY AND INSTRUMENT
## I Background Information:
A 510(k) Number
K253756
B Applicant
Roche Molecular Systems, Inc.
C Proprietary and Established Names
cobas liat CT/NG nucleic acid test
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| QEP | Class 2 | 866.3393 – Device to detect nucleic acids from non-viral microorganism(s) causing sexually-transmitted infections and associated resistance marker(s) | Microbiology |
## II Submission/Device Overview:
A Purpose for Submission:
To obtain market clearance for an additional specimen type, female urine.
B Measurand:
Chlamydia trachomatis (CT) cryptic plasmid DNA and 23S ribosomal RNA Neisseria gonorrhoeae (NG) pivNG and NGR9 DNA
C Type of Test:
Qualitative, real time nucleic acid amplification test (NAAT)
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
{1}
K253756 - Page 2 of 9
## III Intended Use/Indications for Use:
### A Intended Use(s):
See Indications for Use below.
### B Indication(s) for Use:
The cobas liat CT/NG nucleic acid test is an automated, qualitative in vitro nucleic acid diagnostic test that utilizes real-time polymerase chain reaction (PCR) for the direct detection of *Chlamydia trachomatis* (CT) and *Neisseria gonorrhoeae* (NG) in male/female urine and vaginal swabs, all in cobas PCR Media (Roche Molecular Systems, Inc.).
This test is intended as an aid in the diagnosis of urogenital infections in both symptomatic and asymptomatic individuals.
### C Special Conditions for Use Statement(s):
Rx – For Prescription Use Only
### D Special Instrument Requirements:
To be used on the Roche cobas liat system only
## IV Device/System Characteristics:
### A Device Description:
The cobas liat CT/NG nucleic acid test is performed on the cobas liat analyzer which automates and integrates sample purification, nucleic acid amplification, and detection of the target sequence in biological samples using real-time PCR assays. The assay targets both the Cryptic plasmid and 23S rRNA of CT, and the pivNG and NGR9 of NG. An Internal Control (IC) is also included. The IC is present to control for adequate processing of the target bacteria through steps of sample purification, nucleic acid amplification, and to monitor the presence of inhibitors in the PCR processes. The cobas liat CT/NG nucleic acid test requires the following:
1. A cobas liat CT/NG assay tube which contains the following:
- Internal process control (IPC)
- PCR mastermix (assay specific oligonucleotides and polymerase)
- Co-factor, liat magnetic particles, Lysis buffer, Wash buffer, and Elution buffer
2. Specimen sample stored in cobas PCR Media
3. cobas liat CT/NG/MG Control Kit
- Contains positive and negative control tubes for validating new cobas liat CT/NG/MG assay tube lots.
4. cobas liat System
5. liat Assay Specific Package (LASP)
### B Principle of Operation:
A specimen in cobas PCR Media is collected and then transferred into the assay tube using a transfer pipette. The assay tube is loaded into the analyzer and processing begins. The cobas liat assay tube uses a flexible tube as a sample processing vessel and contains all requisite PCR
{2}
reagents pre-packed in tube segments that are separated by breakable seals. When a cobas liat assay tube containing a raw biological sample is inserted into the cobas liat analyzer, multiple sample processing actuators in the cobas liat analyzer compress the cobas liat assay tube to selectively release the reagents, moving the sample from one segment to the next, and controlling reaction conditions.
The analyzer automates sample preparation by mixing the sample with an internal control, lysis reagents and liat Magnetic Particles, which are then incubated for nucleic acid binding to the liat Magnetic Particles, and then washed to remove possible inhibitors. Subsequently, the nucleic acid is eluted from the liat Magnetic Particles, mixed with MasterMix and cofactor, and transferred alternately between assay tube segments at different temperatures for rapid PCR amplification and real-time detection.
An embedded microprocessor controls and coordinates these actions to perform all required assay processes with no user intervention required. The detection unit monitors the reaction in real-time while an on-board computer analyzes the collected data and outputs an interpreted result. All assay steps are performed within the closed and self-contained cobas liat assay tube, minimizing cross-contamination between samples. The sample to result time is approximately 20 minutes
## C Instrument Description Information:
1. Instrument Name:
cobas liat system
2. Specimen Identification:
The cobas liat system maintains positive identification of each sample and assay tube during processing and analysis by means of barcode labels.
Before starting a run, the user is required to scan the assay tube barcode and then scan the sample barcode. The user then transfers the sample into the assay tube and is required to scan the assay tube barcode again before inserting the assay tube into the analyzer and starting the run
3. Specimen Sampling and Handling:
Specimen sampling and handling during the assay is controlled automatically using multiple sample processing modules contained within the cobas liat System.
4. Calibration:
Not applicable
5. Quality Control:
## External Control
Before using a new lot of cobas liat CT/NG assay tubes, the "Lot Validation" procedure must be performed on the analyzer to validate the cobas liat CT/NG assay tube lot. The procedure includes running a negative control and a positive control in separate runs. After processing
K253756 - Page 3 of 9
{3}
is completed for each control, the system will inform the user that the control result has been accepted. The user can now use that specific lot of assay tubes for processing samples.
## Internal Control
An armored RNA is included in the cobas liat CT/NG assay tube. This control acts to monitor the successful execution of the entire assay, from nucleic acid extraction from the targeted microorganisms, amplification, and detection and reporting. The internal control also acts to identify any PCR inhibitors detected in the sample.
## V Substantial Equivalence Information:
A Predicate Device Name(s): cobas 6800/8800 CT/NG
B Predicate 510(k) Number(s): K202408
C Comparison with Predicate(s):
| Device & Predicate Device(s): | K253756 | K202408 |
| --- | --- | --- |
| Device Trade Name | cobas liat CT/NG | cobas 6800/8800 CT/NG |
| | | |
| Intended Use/Indications For Use | The cobas liat CT/NG nucleic acid test is an automated, qualitative in vitro nucleic acid diagnostic test that utilizes real-time polymerase chain reaction (PCR) for the direct detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in male/female urine and vaginal swabs, all in cobas PCR Media (Roche Molecular Systems, Inc.).
This test is intended as an aid in the diagnosis of urogenital infections in both symptomatic and asymptomatic | The cobas CT/NG on the cobas 6800/8800 system is an automated, qualitative in vitro nucleic acid diagnostic test, that utilizes real-time polymerase chain reaction (PCR), for the direct detection of Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (NG) DNA in male and female urine, clinician-instructed self-collected vaginal swab specimens (collected in a clinical setting), and clinician-collected vaginal swab specimens, endocervical swab specimens, oropharyngeal (throat) swab specimens and |
K253756 - Page 4 of 9
{4}
| | individuals. | anorectal swab specimens all collected in cobas PCR Media (Roche Molecular Systems, Inc.), and cervical specimens collected in PreservCyt solution. This test is intended as an aid in the diagnosis of chlamydial and gonococcal disease in both symptomatic and asymptomatic individuals. |
| --- | --- | --- |
| Sample Preparation | Automated | Same |
| Amplification Technology | Real-Time PCR | Same |
| Analyte Targets | Detection CT or NG | Detection CT or NG |
| Specimens Utilized | Male urine
Female urine
Vaginal swab | Male urine
Female urine
Self-collected vaginal swab
Clinician-collected vaginal swab
Endocervical swab
Endocervical specimen in PreservCyt
Oropharyngeal (throat) swab
Anorectal swab specimens |
| Detection Chemistry | Assay using different reporter dyes for targets and control | Paired reporter and quencher fluorescence labeled probes (TaqMan Technology) using fluorescence resonance energy transfer (FRET) |
| | | |
VI Standards/Guidance Documents Referenced:
Class II Special Controls as per 21 CFR 866.3393
VII Performance Characteristics (if/when applicable):
A Analytical Performance:
K253756 - Page 5 of 9
{5}
1. Precision/Reproducibility:
See previous submission, K240217
2. Linearity:
Not applicable.
3. Analytical Specificity/Interference:
See previous submission, K240217
4. Detection Limit and Assay Reportable Range:
See previous submission, K240217
5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
See previous submission, K240217
6. Assay Cut-Off:
See previous submission, K240217
## B Comparison Studies:
1. Method Comparison with Predicate Device:
See Clinical Studies section below
2. Matrix Comparison:
Not applicable
## C Clinical Studies:
1. Clinical Performance:
Clinical performance for the cobas liat CT/NG nucleic acid test for vaginal swab and male urine specimens is described in K240217.
Clinical performance of the cobas liat CT/NG nucleic acid test in female urine specimens was established in a multi-site, prospective study (described in K240217) comparing the results to a Composite Comparator Algorithm (CCA) for CT and NG. CCA for CT and NG was derived from testing female urine specimens on three FDA-cleared NAATs. The subject was considered positive for CT and NG if two out of three comparator NAATs were positive. The subject was considered negative for CT and NG if two out of three NAATs were negative. Female urine specimens were collected and tested at 13 geographically diverse
K253756 - Page 6 of 9
{6}
intended use clinical sites across the US. There were 48 operators that took part in cobas liat CT/NG testing, of which, 43 represented CLIA-waived operators. Five of the 48 operators represented experienced laboratorians in a moderate complexity laboratory. A total of 2512 female subjects were enrolled in the study and provided specimens for collection. Of the evaluable subjects, there were 2459 specimens included in the final clinical performance. Subjects provided a urine specimen that was aliquoted into the respective manufacturers' collection devices and cobas PCR Media.
A supplemental study was conducted to evaluate the performance of cobas liat CT/NG nucleic acid test for the assessment of detecting CT in female urine specimens. Specimen collection was performed at one external site. Nine operators with minimal or no hands-on laboratory training performed the testing. There were a total of 785 prospective samples from subjects who met the study eligibility criteria. Of these 785 samples, there were a total of 751 samples with evaluable results and included in the final data set. The final evaluation was determined by comparing results from cobas liat CT/NG nucleic acid test to CCA.
Analysis of both studies show that the cobas liat CT/NG nucleic acid test detected $8.4\%$ fewer CT infections and $6.9\%$ fewer NG infections in female urine when compared to a vaginal swab CCA versus a female urine CCA. Clinical performance of the cobas liat CT/NG nucleic acid test is shown in Tables 1 and 2.
Table 1: CT Clinical Performance in Female Urine against the CCA Result
| Study | Symptom Status | N | TP | FP | TN | FN | PPA (95% CI) | NPA (95% CI) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Supplemental Study | Symptomatic | 312 | 17 | 2 | 293 | 0 | 100% (81.6%-100%) | 99.3% (97.6%-99.8%) |
| Supplemental Study | Asymptomatic | 439 | 15 | 3 | 420 | 1 | 93.8% (71.7%-98.9%) | 99.3% (97.9%-99.8%) |
| Supplemental Study | Overall | 751 | 32 | 5 | 713 | 1 | 97.0% (84.7%-99.5%) | 99.3% (98.4%-99.7%) |
| K240217 Study | Symptomatic | 1113 | 53 | 2 | 1054 | 4 | 93.0% (83.3%-97.2%) | 99.8% (99.3%-99.9%) |
| K240217 Study | Asymptomatic | 1346 | 40 | 3 | 1302 | 1 | 97.6% (87.4%-99.6%) | 99.8% (99.3%-99.9%) |
| K240217 Study | Overall | 2459 | 93 | 5 | 2356 | 5 | 94.9% (88.6%-97.8%) | 99.8% (99.5%-99.9%) |
| Combined | Symptomatic | 1425 | 70 | 4 | 1347 | 4 | 94.6% (86.9%-97.9%) | 99.7% (99.2%-99.9%) |
| Combined | Asymptomatic | 1785 | 55 | 6 | 1722 | 2 | 96.5% (88.1%-99.0%) | 99.7% (99.2%-99.8%) |
| Combined | Overall | 3210 | 125 | 10 | 3069 | 6 | 95.4% (90.4%-97.9%) | 99.7% (99.4%-99.8%) |
Table 2: NG Clinical Performance in Female Urine against the CCA Result
| Symptom Status | N | TP | FP | TN | FN | PPA (95% CI) | NPA (95% CI) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Symptomatic | 1111 | 20 | 1 | 1090 | 0 | 100% (83.9%-100%) | 99.9% (99.5%-100%) |
| Asymptomatic | 1347 | 17 | 1 | 1329 | 0 | 100% (81.6%-100%) | 99.9% (99.6%-100%) |
| Overall | 2458 | 37 | 2 | 2419 | 0 | 100% (90.6%-100%) | 99.9% (99.7%-100%) |
K253756 - Page 7 of 9
{7}
K253756 - Page 8 of 9
2. Clinical Cut-Off
Not applicable
D Expected Values/Reference Range:
Table 3: Positivity rate for the cobas liat CT/NG nucleic acid test in female urine specimens during the study by collection site is shown below.
| Collection Site | CT | NG |
| --- | --- | --- |
| 1 | 6.6%
(10/151) | 2.0%
(3/151) |
| 2 | 5.4%
(13/240) | 3.8%
(9/240) |
| 3 | 7.4%
(27/365) | 0.6%
(2/362) |
| 4 | 0.0%
(0/161) | 1.2%
(2/161) |
| 5 | NC | NC |
| 6 | 2.4%
(2/83) | 0.0%
(0/83) |
| 7 | 7.5%
(3/40) | 2.5%
(1/40) |
| 8 | 0.0%
(0/17) | 0.0%
(0/17) |
| 9 | 1.9%
(10/524) | 1.5%
(8/526) |
| 10 | 0.9%
(3/348) | 0.9%
(3/348) |
| 11 | 4.6%
(14/304) | 2.3%
(7/304) |
| 12 | 9.6%
(13/136) | 1.5%
(2/136) |
| 13 | 4.0%
(4/101) | 2.0%
(2/101) |
| 14 | 4.9%
(37/751) | - |
NC: non calculable as no female subjects were enrolled at this site
E Other Supportive Instrument Performance Characteristics Data:
Not applicable.
VIII Proposed Labeling:
The labeling supports the finding of substantial equivalence for this device.
IX Conclusion:
{8}
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
K253756 - Page 9 of 9
