Mycoplasma genitalium screen and resistance assay
The Cobas® Mycoplasma Genitalium (MG) assay is a qualitative in vitro diagnostic test, that utilizes real-time polymerase chain reaction (PCR), for the direct detection of MG DNA in male and female urine, clinician-instructed self-collected vaginal swab specimens, clinician-collected vaginal swab specimens, endocervical swab specimens, clinician-instructed self-collected meatal swab specimens, clinician-collected meatal 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 MG caused disease in both symptomatic and asymptomatic individuals.
The Elitech resistance assay detects the macrolide resistance gene and will be performed on all samples that have tested positive for MG on the Cobas MG assay.
Mycoplasma genitalium is a fastidious bacterium first isolated in 1980 from the urethral swabs of two symptomatic men with non-gonococcal urethritis (NGU). Infections caused by this bacterium have been associated with male and female urethritis, balanoposthitis, prostatitis, cervicitis, pelvic inflammatory disease, and male and female infertility. Additional complications, such as preterm delivery and extra-genital infections, have been reported.
Positive with resistance gene detection
Negative
See Notes section below for guides to PCR Media Urine Collection Kit; PCR Media Swabs Guide; PCR Clinician Collected Vaginal and Endocervical Samples
Please click here to view collection guide – cobas PCR Media Urine Collection Kit
Please click here to view collection guide – cobas PCR Media Swabs Guide
- Reliable results depend on proper sample collection, storage and handling procedures.
- The cobas® MG assay has been validated for use with male and female urine, clinician-instructed self-collected vaginal swab specimens, clinician-collected vaginal swab specimens, clinician-instructed self-collected meatal swab specimens, clinician-collected meatal swab specimens, and endocervical swab specimens, all collected in cobas® PCR Media (Roche Molecular Systems, Inc.) and cervical specimens collected in PreservCyt® Solution. Assay performance has not been established with other collection media and/or specimen types. Use of other collection media and/or specimen types may lead to false positive, false negative or invalid results.
- The cobas® MG assay has not been evaluated in patients younger than 14 years of age.
- Detection of M. genitalium is dependent on the number of organisms present in the specimen and may be affected by specimen collection methods, patient factors (i.e., age, history of STD, presence of symptoms), stage of infection and/or infecting M. genitalium strains.
- The cobas® MG assay for urine testing is recommended to be performed on first catch urine specimens (defined as the first 10 to 50 mL of the urine stream). The effects of other variables such as first-catch vs. mid-stream, post-douching, etc. have not been evaluated.
- The effects of other potential variables such as vaginal discharge, use of tampons, douching, etc. and specimen collection variables have not been evaluated.
- The cobas® MG assay has not been evaluated with patients who were currently being treated with antimicrobial agents active against MG as well as patients with a history of hysterectomy.
- Urogenital specimens from patients who have used the over-the-counter products ReplensTM Long-Lasting Vaginal Moisturizer, RepHreshTM Clean Balance or used Metronidazole Vaginal Gel (Sandoz) may generate invalid or false negative results. In general the presence of PCR inhibitors may cause false negative or invalid results.
- Though rare, mutations within the highly conserved regions of the genomic DNA of M. genitalium covered by cobas® MG primers and/or probes may result in failure to detect the presence of the bacterium.
The Cobas assay and Elitech macrolide resistance assay is awaiting UKAS accreditation due to a change in assay platform.
Record last updated
February 17, 2026
Sample Container
Cobas PCR Media Uni Swab (Viral swab)
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Test Results
Yes, we have a Pathology User Guide
Yes. Please email your request to Imperial.nwlpcustomerservice@nhs.net
Results are communicated to clinical staff and are normally not communicated direct to patients either on telephone requests or in written report. If you need to contact us please click here to view the contact details page
Please contact the Customer Service Team Monday to Friday from 8:30am – 6:00pm on 0203 313 5353. Alternatively, see the Pathology User Guide for how to contact the relevant department. If advice is not urgent you can also email your query to Imperial.nwlpcustomerservice@nhs.net
Additional tests may be added by discussion with the relevant laboratory. The time limit for adding additional tests to a sample already received in the laboratory will depend on the type of sample and the department it was sent to.
Information on the repertoire of tests performed by pathology, including reference ranges, turnaround times and specimen requirements, can be found in the test directory.
Different tests have different sample stability requirements. If a comment on results indicates that the sample was delayed, the links below will indicate which tests may have been affected. This information is for serum or plasma samples.
For some tests, the impact of delay is consistent and these are marked with an arrow:
↑ indicates tests where delayed centrifugation results in falsely elevated results and the true level is likely lower than that reported.
↓ indicates tests where delayed centrifugation results in falsely lowered results and the true level is likely higher than that reported.
If there is no arrow, the true level may be lower or higher than reported.
Please interpret results with caution and consider the impact of any uncertainty.
The comment on the report will state how delayed the sample was. Please click the relevant link below to see which other tests may have been affected.
| >8h | >12h | >24h | >48h | >72h |
Phlebotomy services are not managed by NWLP. For further information please see:
Imperial College Healthcare Trust Phlebotomy services
Chelsea and Westminster Hospital NHS Foundation Trust Phlebotomy services
NWLP operates UKAS accredited medical laboratories as per the references below. The current scope of accreditation for all NWLP’s laboratories can be found on the UKAS website.
UKAS accredited medical laboratory/medical diagnostic service:
- Clinical Biochemistry No. 8673
- Haematology and Blood Transfusion No. 8674
- Infection & Immunity Sciences (Including Immunology, Virology, Microbiology and Histocompatibility and Immunogenetics ) No. 8659
- Cellular Pathology (Including Histopathology, Cytology and Molecular Pathology) No. 9615
If you require copies of our certificate of accreditation and associated documentation please contact Imperial.nwlpcustomerservice@nhs.net.
UKAS requires the laboratories to be accredited for a particular repertoire/scope (ISO15189), any changes or additions to repertoire require assessment by UKAS (extension to scope).
The BD Hospital Tube Guide, BD GP Tube Guide and BD Paediatric Tube Guide provide visual references to the correct tube types and collection instructions.
Home testing
INSTRUCTION SHEET FOR BLOOD SAMPLE COLLECTION
We also have two instruction videos available (one with subtitles and one without) – please click on the links to view the videos on Google.
Our accreditations
Upholding excellence in diagnostic standards
Our laboratories are accredited by the UK Accreditation Service (UKAS) against the international standard ISO15189:2022. UKAS is the accreditation body for the UK that assesses medical laboratories.
Find out more about our accreditations on the UKAS website.
UKAS website