Testing for group B Strep (GBS) during pregnancy can give you peace of mind and help protect your baby. Here’s everything you need to know about ordering a private test.
Why consider a private test?
- The NHS does not routinely offer GBS testing to everyone.
- Most hospitals do not offer the Enriched Culture Medium (ECM) test – the gold standard test – which takes samples from the low vagina and rectum, and uses an extra enrichment process in the lab.
- The ECM test most reliable way to find out if you carry GBS.
- ECM tests are available from private providers, including using a postal service.
When should I test?
- Best time: Between 35 and 37 weeks of pregnancy.
- Why? Testing in this window gives the most accurate prediction of whether you’ll carry GBS at birth.
- Testing earlier is possible but the results may be less reliable.
- Testing later is possible but the results may not be available until after birth
How does the home-test work?
- Order a kit from a recommended provider.
- Take two swabs – one from the low vagina and one from just inside the rectum (instructions included).
- Post the samples back to the lab (Mon–Thu to avoid postal delays).
- Get your results – usually within 3 working days.
What does it cost?
From around £50 for the kit, including lab analysis and results.
Where can I order a test?
GBSS works with trusted providers who meet strict quality standards. Our preferred provider is The Doctors Laboratory (TDL).
(GBSS does not earn commission from test providers, though some support GBSS through donations.)
What if my test is positive?
Carrying GBS is common and not harmful to you.
Tell your midwife or doctor.
You’ll usually be offered antibiotics once labour has started to help protect your baby.
Important Tips
✅ Order your kit early so you’re ready to test at 35–37 weeks.
✅ Avoid antibiotics before testing if possible (they can affect results).
✅ Post samples Mon–Thu to avoid delays.
✅ Keep your results safe and share them with your maternity team.
Quick Comparison: ECM vs Standard NHS Test
ECM Test (available through TDL)
| Accuracy | High |
| Availability | Some NHS hospitals + privately |
| Cost | ~£50 |
Standard NHS Test (usually HVS)
| Accuracy | High if positive, low if negative |
| Availability | Not widely used for GBS testing |
| Cost | Free (if offered) |
If you have any questions about TDL’s service, please contact them directly on 0207 307 7373 or email them at gbs@tdlpathology.com .
Most pregnant women and people cannot easily access GBS testing through the NHS. GBSS partners with selected companies which sell the ‘gold standard’ GBS test kits privately.
The charity partners only with selected companies that provide Enriched Culture Medium (ECM) tests. ECM tests are internationally recognised as the ‘Gold Standard’ tests for GBS carriage. ECM tests are much more reliable than a standard NHS swab test – you can read more about the different tests for GBS here.
All partners with GBSS have met strict criteria set by GBSS and its medical advisors before being considered for promotion on its website and in its social media channels. Companies on this page support the charity’s vital work financially, enabling us to reach more families with information about group B Strep.
Collecting the required swab samples, both from the low vagina and just inside the rectum, is straightforward. The DIY kits come with comprehensive instructions and a visual guide to help.
If you use a group B Strep home testing pack, please follow the instructions carefully and keep the insert for future reference.
To ensure sample quality, it’s advisable to send the swabs to the laboratory between Monday and Thursday, so they’re not sitting in the postal system longer than necessary, as the samples deteriorate over time.
If you are or have recently been taking antibiotics, please be aware this may affect your GBS test result. Please discuss this with your health professional.
Please note that we at GBSS receive no commission or referral fees from test sales, though companies listed on this page may make donations to the charity to support our work.
If you have any questions about group B Strep, please email our helpline
Mon-Fri 9am-5pm
Or call us on 0330 120 0796
