Check our a wide range of frequently asked questions and answers below.

Can I take an STI test when I'm on my period?

Yes. However, if you wait until the lighter days of your period or until you have stopped bleeding your test results are likely to be more accurate.

Can I take an STI test when I'm pregnant?

Yes. The swab is inserted into the lower part of the vagina and will not affect the baby in anyway. The test is just as accurate if taken when you are pregnant.

What happens if I have an infection?

As soon as your test results become available, we will send you a text message to let you know. If you have an infection, an NHS clinician will then call you to discuss your treatment.

Who will see my results?

Regardless of whether you have an infection or not, only trained NHS clinicians and SH:24 service managers will see your test results. All SH:24 staff sign a data protection agreement, similar to that used by other NHS staff. Your results will never be shared with anyone else without your permission.

How accurate/reliable are the results?

No STI test is 100% accurate. It can take time for some STIs to show up in tests, this is referred to as the incubation period so find out when STIs show up in tests before you take one.

A test result that shows a possible infection is called 'reactive'. For HIV testing, a 'reactive' test will require further investigation to confirm the result. False reactives are rare but do happen.

Do you test for BV (Bacterial Vaginosis)?

You can get tested for BV at your local clinic, but this test is not available through online testing.

How will I receive my STI test results?

Most people will receive their results by text message. However, in some cases an NHS clinician will call to discuss your test results and treatment.

Who will deliver my test kit?

Your test kit will be delivered by Royal Mail in a plain envelope. Neither ‘SH:24’ nor ‘NHS’ will appear on the outside of the envelope. It will be sent by standard post, meaning that a signature is not required. The envelope will fit through a standard letter box.

When should I just go straight to the clinic?

We would strongly recommend that you visit a clinic as soon as you can, if one or more of the following applies to you:

  • If you have been sexually assaulted
  • If you are a man who has sex with men and have had unprotected sex in the last three days
  • If you have any symptoms
  • If you are a woman and have had unprotected sex in the last five days and think you are at risk of being pregnant
  • If you are under the age of 16.

What if I don't want to be tested for all four STIs?

We appreciate that some people may not wish to be tested for one or more of the STIs we test for. In some regions we offer people a choice of tests (agreed by the commissioning Local Authority and/or healthcare provider in that region). If you are not offered the opportunity to choose which STIs you would like to be tested for, we suggest you visit your nearest clinic instead. Remember, all of your results are confidential.

Do I have to do the blood test?

We appreciate that some people may not wish to provide a blood sample. If you do not return a blood sample, we will be unable to test for Syphilis or HIV. In some regions we offer people a choice of tests (agreed by the commissioning Local Authority and/or healthcare provider in that region). Remember, all of your results are confidential.

Can I request to be forgotten?

Under revised data protection laws you have the right to be forgotten. If you would like to be forgotten, text CANCEL to 07860 041 233.

It is important that you make your request before we dispatch your order (so we can cancel your order immediately and erase all of your data).

This applies for online testing.

Will my results be shared with anyone else?

Your results will never be shared with anyone else, in or outside the NHS, without your permission.

If I have an STI will I have to go to a sexual health clinic?

If you have an infection you will need to visit a clinic to receive treatment. An NHS clinician will be available to discuss your treatment with you.

What is the relationship between SH:24 and the NHS?

We work in close partnership with NHS Trusts across the country to offer the highest quality of sexual health advice, support and treatment. SH:24 is a Community Interest Company formed of both NHS Trusts and local authorities.

What if I lose my mobile phone before I get my results?

If you lose your mobile phone after you have ordered a test kit, please contact us as soon as possible, quoting your name, date of birth and postcode, and a new mobile telephone number (if you have one). Email us at: or text us on: 07860 041 233.

Do you test for Hepatitis B and/or Hepatitis C?

No. We currently test for Chlamydia, Gonorrhoea, Syphilis and HIV. If you would like to test for Hepatitis (B or C) we would recommend you visit your local clinic.

What is a discordant result?

SH:24 uses highly sensitive & specific diagnostic tests for HIV, Syphilis, Chlamydia and Gonorrhoea; however, when tens of thousands of tests are done each year it is possible for unexpected results to occur.

One reason for this is contamination, which can occur at the time of sampling or in the laboratory. The molecular amplification tests we use are very powerful and the smallest trace of the organism can result in a positive or reactive result. Since you are testing at home contamination is unlikely and our partner laboratory abide by strict quality controls to ensure that cross contamination does not occur; consequently, it is highly unlikely for the test result for Chlamydia & Gonorrhoea to be wrong.

When SH:24 refers you to a service for treatment for Chlamydia & Gonorrhoea we do not expect the clinic to repeat the test at this time; however, in some rare circumstances when the result does not match the clinical history the clinic you visit may opt to repeat the test and wait for that result.

What should I do if my test kit does not arrive?

If your test kit does not arrive in the post within three working days, please contact us as soon as possible, quoting your name, date of birth and postcode. Email us at: or text us on: 07860 041 233.

What if I don't have a smart phone?

You don’t need a smart phone to use SH:24. If you have a traditional handset, our text messages may be delivered to you in two or three parts, but you will receive the same information and same level of service. You can view our website and order a test kit on any mobile device, laptop or PC that is connected to the internet.

Should I let my previous partners know if I have an STI?

If you have an infection you should tell all of your current partners and anyone else that you have had sex with in the last 6 months. They may have an STI without knowing it, and may be passing it on to other people, so it is important for them to be tested. We know that you might find this difficult, so if you have an infection an NHS clinician will discuss notifying your partners with you. 

What testing platforms do SH:24 use?

Chlamydia & Gonorrhoea

SH:24's laboratory test for chlamydia and gonorrhoea using the Becton Dickinson Viper XTR platform. Confirmatory testing is carried out on the Cepheid GeneXpert (dual target) confirmatory test.

HIV & Syphilis

SH:24's laboratory screen for HIV and syphilis using the Roche Cobas E Modular platform and Roche ElectroChemiLuminescence ImmunoAssay (ECLIA) respectively. All HIV and syphilis results require confirmatory testing in a clinic.

A test result that shows a possible infection is called 'reactive'. False reactives are rare but do happen, due to the sensitivity of these testing platforms.

Can I find out more about HIV testing?

FAQs about testing for HIV

The definitions below may be useful when reading these FAQs about HIV:

  • HIV - Human Immunodeficiency Virus
  • Antibody -something your body produces to fight an infection
  • Antigen - a part of the virus or bacteria causing an infection that a test may detect
  • Point of Care Test (POCT) - a test that is done by a health care professional with the patient present that gives an instant result
  • Micro-container - the container that SH:24 uses to collect blood samples to send to the laboratory
  • Screening test - a test that looks for the likelihood of an infection or disease being present but is not a definite diagnosis – other tests are needed to confirm the disease or infection is present
  • Diagnostic test - a test or group of tests that are used to confirm the presence of a disease or infection (often done after a screening test)
  • Reactive - a term used for a screening test that means the test has suggested the presence of infection but needs to be confirmed
  • Positive - a term that is used with more confidence when a test or group of tests confirms the presence of a disease or infection
  • Sensitivity - a measure of how accurately a test can confirm an infection is present (a very sensitive test would have very low or no false negatives)
  • Specificity - a measure of how accurately a test can exclude that an infection is present (a very specific test would have very low or no false positives)
  • Window period - the time it takes from someone catching an infection to when it can be confidently detected by a test

What does ‘reactive’ mean, and why do I need to have another test?

In order to make testing at home as easy as possible, SH:24 uses a finger prick test and collects a small blood sample in the micro-container. The micro-container is the name of the little bottle you collect your blood sample in. When the sample reaches the laboratory they do a screening test to look for the presence of HIV antibodies. If this is positive, they repeat the screening test. If it is positive a second time the test is called ‘reactive’. This means it looks like HIV is present but it has not been confirmed.

It is not possible to confirm a positive result on the micro-container sample – this is because of the sensitivity and specificity of the test (see definitions above). So a ‘reactive result’ may be a true positive – but it may also be a ‘false positive’. This is why all ‘reactive’ test results need to be referred into clinic for further blood tests before an HIV positive diagnosis can be made.

An HIV-negative result can be confidently given on the small blood sample we send to the lab. This is because the test is very sensitive and we don’t expect any false negatives as long as the test has been done within the window period of the test (4 weeks).

How common are reactive results and how many of these are false positives?

False positives are rare. In the first six months of 2016 – SH:24 processed 7,297 HIV tests.

  • Of these, 55 (less than 1% of all HIV tests processed) had a reactive result
  • 30 of these reactive results were confirmed true positives
  • 7,242 of these results were true negatives
  • and 25 were confirmed as false positives – this gives a false positive rate of 0.3% (25/(25+7297)

What is the difference between a POCT and an HIV test on SH:24?

The HIV test that SH:24 uses tests for HIV 1 & 2 and looks for both p24 antigen (part of the virus) and antibody (what the body’s immune system makes to fight the virus). The sample has to be sent off to the laboratory for testing and you receive your result by text in a few days.

There are different types of point of care test (POCT). Some of them just test for HIV 1 & 2 antibody and one tests for both HIV antibody and p24 antigen. Different clinics will use different tests. The main difference is that with a POCT you get the result immediately (within 20 minutes depending on which test is used). Like SH:24’s HIV test, POCTs are also screening tests and give a ‘reactive’ result which needs to be confirmed with a blood test sent to the laboratory.

What is the difference between generations of HIV tests?

Most HIV antibody tests are in an ELISA or EIA format (enzyme-linked immunosorbent assay).
Third-generation HIV tests are in an ELISA format (enzyme-linked immune-absorbent assay) and screen for HIV antibodies and not the virus itself.

Fourth-generation tests, introduced in the late 1990s, are ELISAs which test for both HIV antibodies and p24 antigen. Testing for p24 antigen can help detect HIV earlier than tests that only test for HIV antibodies which shortens the window period. Different tests have different window periods depending on how quickly after infection they are likely to detect HIV.

Could I get a false positive HIV result because I have another condition?

False positive results are rare and occur in less than 0.3% of cases.

A false positive can be the result of a recent flu vaccination, current or recent viral infections and sometimes multiple pregnancies. More rarely, false positive results have been reported as a result of a small number of other medical conditions and vaccines, though such results are unusual. Most commonly there is no obvious reason for a false positive and they often happen in healthy people. This may be because other normal antibodies that are present in the blood ‘cross react’ or ‘confuse’ the test.

Why do I have to have another test to confirm an HIV reactive result?

Nobody should be told they are HIV positive based on the result of a single test – this is why we call the HIV result ‘reactive’. Following a reactive result on the SH:24 HIV test, you will be referred into clinic where you will  be offered a further screening test which is a blood test taken from your arm with a syringe – this allows the clinic to get a larger sample of blood which they can send to the laboratory to run a sequence of tests for confirmatory testing.

The principle of this multiple testing strategy is that the screening test used should have a very high sensitivity (i.e. you don’t expect any false negatives). In other words, they will detect all people who are truly HIV negative. But the test may also incorrectly report as positive a small number of people who are not infected at all i.e. a small false positive rate – this is because the test is not 100% specific. This is why we refer all reactives in for confirmatory testing.

For more on screening see:   

What are the differences between HIV 1 and 2?

There are two major types of the human immunodeficiency virus. HIV-1, which was discovered first, is the most widespread type worldwide. HIV-2 is most common in people of west African origin. HIV-2 is very rare in the UK – with just a few hundred people infected with this strain (<1%). Both viruses, if untreated, will result in AIDS and the infection is contracted in the same way.

How secure is the SH:24 website?

All data is stored on an NHS approved server, within an environment called N3. Whilst it is impossible for any website to guarantee security, the standards that SH:24 operates to are judged to be some of the highest in the UK.

Why do you need these samples?

Depending on your gender and sexual preference we will ask you to provide us with samples to test for the four most common STIs: 

Heterosexual Men

  • A urine sample to test for Chlamydia and Gonorrhoea
  • A small blood sample to test for Syphilis and HIV

Heterosexual Women

  • A vaginal swab to test for Chlamydia and Gonorrhoea
  • A small blood sample to test for Syphilis and HIV

Homosexual or Bi Men

  • A urine sample to test for Chlamydia and Gonorrhoea in your urine
  • A oral swab to test for Chlamydia and Gonorrhoea in your mouth
  • A anal swab to test for Chlamydia and Gonorrhoea in your anus
  • A small blood sample to test for Syphilis and HIV

Homosexual or Bi Women

  • A vaginal swab to test for Chlamydia and Gonorrhoea
  • A small blood sample to test for Syphilis and HIV


  • Trans* users will receive a kit according to the genitals they have

Is SH:24 compliant with the General Data Protection Regulation?

SH:24 has undertaken a comprehensive programme of work and received extensive specialist advice to ensure that it is compliant with GDPR. Our website policies have also recently been updated. Read more about our preparation in our GDPR blog post.

What if I am transgender or transexual - which gender should I choose?

We use your gender to help to determine which test kit we send you. For the purposes of ordering an SH:24 test kit, you will need to select your gender based on what genitals you have. If you were born with both sets of genitals, please let us know when ordering, in the 'How else can we help?' box in step 6.

Hide this section
Show accessibility tools