ECM test. Where & how?

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A number of NHS Trusts already offer ECM testing - we understand the following hospitals do, often on request, though some use specific risk factors to determine which women should be offered the ECM test.  There may well be others which also offer the ECM test - it's always worth asking:

ECM GBS testing is the 'gold standard' method for detecting group B Strep carriage.  If the ECM test is not available from your hospital, it is available privately (from around £35 per test for a postal service):

Home Testing Kits (around £35 per test):

A postal service for ECM GBS tests is available from a number of sources.  The cost of the test pack, processing the swabs and sending you the results is approximately £35.  You can watch a YouTube video about self-testing here.

You can obtain your GBS ECM test pack by calling or visiting the websites of the following:

*Health professionals may request multiple testing packs without charge - the pregnant mum pays the laboratory when sending the swabs back for culture.

The test packs/processing for the above all follow Public Health England's UK Standards for Microbiology Investigations B 58, the 'gold standard' for GBS testing, and are undertaken by CPA accredited laboratories. This test uses an enriched culture to selectively grow GBS for testing - and is commonly referred to as an Enriched Culture Medium (or ECM) test.  

[Please note that GBSS simply provides the name and address of laboratories - we don't have the resources to check their performance in terms of speed or accuracy. If anyone would like to provide us with feedback on the services provided, please contact us at]

When you order the GBS Test Pack from a private firm, it is usually sent out the same day. Once received, then the swabs can be taken either by the pregnant woman herself (following simple instructions on the pack - this is fine, many women do without difficulty), or by her health professional (who may charge a fee for the sample collection). Either way, the pregnant woman’s health professional should also be sent a copy of the results – the form allows space for this information to be given.

When you complete the request form enclosed with the sample pack, you will see that there is an option to receive your result by SMS Text Message.  A GBS GREEN message means the result for GBS is NEGATIVE and intravenous antibiotics are not indicated.  A GBS RED message means the results for GBS is POSITIVE during your pregnancy and means that intravenous (not oral) antibiotics should be offered from the onset of labour and then at intervals until delivery.  Turnaround time for the results is within three days of receipt of your swabs in the laboratory.  The recommended time for taking the swabs is 35 - 37 weeks of pregnancy.

Tests at a Private Clinic:

The following laboratories provide a more personal service for ECM GBS testing, whilst still following the Public Health England's UK Standards for Microbiology Investigations B 58

You can make an appointment to see them; they can take the swabs for you (or you take them yourself) and will send you the results by post, email or text.  The charges may be higher for this personal service.  These laboratories are:

What does this ECM test involve?

There are two swabs - one for the entrance to the vagina and the other for the rectum.  The private test packs contain straightforward instructions.  The swabs should ideally be taken between 35-37 weeks of pregnancy – they can be done earlier but then they may not be as reliable in predicting GBS carriage at delivery. They may be done later, but then there’s an increasing chance that the baby will be born before the test result is available. The swabs are then sent direct to the laboratory (with payment) in the envelope provided as part of the GBS Test Pack.

Each of the private laboratories above undertakes to have the results available within three working days of receipt of the swabs and to send out the results on that day to the health professional, with if requested a copy to the pregnant woman. As there is no post on Sundays, it may therefore be preferable to take and send off the swab sample towards the beginning of the week.

Because the swabs and the results are sent through the post, the postal ECM GBS test can be done anywhere in the UK.

Group B Strep Support endorses the availability of reliable prenatal GBS testing but has no links to nor receives any money from any particular laboratory. Indeed, we hope that many other laboratories will offer this test. And, as they do, we'll provide details of their service also.

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