Frequently Asked Questions
Medical content reviewed by:
Dr Gillian Holdsworth, Fettle's Managing Director, Medical Doctor and public health expert.
What is the relationship between Fettle, SH:24 and the NHS?
SH:24 is commissioned by local authorities around the UK to deliver sexual and reproductive health services. As a community interest company, all of SH:24’s profits are reinvested into improving public health services. SH:24 works in close partnership with NHS Trusts and other healthcare providers across the UK to offer the highest quality sexual health advice, support and treatment. Our in-house clinical support team are all qualified clinicians.
Fettle is powered by SH:24. This means that we share a clinical and administrative team, and that our service development is informed by learning from how SH:24 operates, and what works for our users.
Fettle’s profits are channelled back into SH:24’s service development.
Why is SH:24 free and Fettle is not?
SH:24 is commissioned by public bodies to deliver sexual and reproductive health services in specific areas. This means that the service is free at the point of use, as it is paid for by the local public health budget.
However, because of the way health services are commissioned, and partly due to pressure on public health budgets, SH:24 is not able to offer a free service to everyone, everywhere.
We set up Fettle because we wanted to offer the same quality and ease of service to everyone, no matter where you live in the UK. We recognise that some people are willing or able to pay for services which they could get for free on the NHS, but which they might have to wait for. We want to provide a service that is easy to use, affordable, and with the same level of clinical quality and care as you would receive from the NHS. We need to charge for this service in order to cover the costs of delivery. Any profit generated is reinvested into service development or back intoSH:24, in order to improve public health services for anyone, regardless of what they can afford.
How secure is the Fettle website?
Who will see my details?
Regardless of whether you have an infection or not, only our clinicians and service managers will see your test results. All our staff sign a data protection agreement, similar to that used by NHS staff. Your results will never be shared with anyone else without your permission.
Who will deliver my order?
Your order will be delivered by Royal Mail in a plain envelope. It will be sent by standard post, meaning that a signature is not required. The envelope will fit through a standard letter box.
What does the packaging look like?
Your order will be packaged in a plain and unmarked grey envelope that fits through a standard letter box.
What should I do if my order does not arrive?
If your order 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 firstname.lastname@example.org or text us
What if I don’t have a smartphone?
You don’t need a smartphone to use this service. 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.
What if I lose my mobile phone or change my mobile number?
If you lose your mobile phone after you have made an order, 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 email@example.com or text us on
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 any symptoms
- if you are a man who has sex with men and have had unprotected sex in the last three days
- 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
- if you have been sexually assaulted.
What samples will I need to provide?
This depends on your gender and what tests you choose to order. Trans* or non-binary users will receive a kit according to the genitals they have.
Chlamydia and Gonorrhoea:
We offer tests for different parts of your body.
- urine sample (penis)
- vaginal swab
- rectal swab
- oral swab.
Syphilis, HIV, Hepatitis B and Hepatitis C
- small blood sample from a finger prick.
How will I receive my STI test results?
Most people receive their results by text message. In some cases, one of our clinicians will call you to discuss your test results and treatment.
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 how to get treatment.
If you receive a positive chlamydia test result from Fettle, we will offer you free treatment and deliver it by 1st class Royal Mail. (For genital infections only, not oral or rectal.) Before we prescribe, you will need to complete a short online form, answering questions about you and your health history.
If you return a reactive result for HIV, Syphilis or Hepatitis B or C, a member of our dedicated clinical team will call you and offer you additional support.
What if I am transgender or transexual - which gender should I choose?
If you are transgender or transexual you can select the ‘trans*’ or ‘non binary’ option when asked to specify your gender in the order form. You will then be asked to specify which genitals you have, we will use this information to ensure we send you the appropriate kit.
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 use the swab whilst I'm pregnant?
Yes. It can be especially important to test for chlamydia during pregnancy as the infection can be passed to the baby during delivery. The swab is inserted into the lower part of the vagina and will not affect the baby in any way. The test is just as accurate if taken when you are pregnant.
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. If you would like advice on how to notify partners for any other infections, email us at firstname.lastname@example.org.
How accurate/reliable are the STI results?
No STI test is 100% accurate. It can take time for some STIs to show up in tests, so find outwhen STIs show up in tests before you take one.
Our partner laboratory works to strict, government enforced protocols to ensure results are as accurate as possible. If you have any concerns about the reliability of your results, we would be happy to talk to you.
A test result that shows a possible infection is called 'reactive'. For HIV, syphilis and Hepatitis B/C testing, a 'reactive' test will require further investigation to confirm the result. False reactives are rare but do happen.
What testing platforms does Fettle use?
Chlamydia and Gonorrhoea
Our screens for Chlamydia & Gonorrhoea are the nucleic acid amplification tests (NAATs) run on the Hologic Panther platform.
HIV and syphilis
Our HIV test may use either 4th or 5th Generation Assay. This tests for HIV I and II/p24 antigen.
Our Syphilis test is an ECLIA (ElectroChemiLuminescence ImmunoAssay). This test looks for antibodies known as immunoglobulin IgG and IgM.
Our laboratory screens for both HIV and syphilis using the Roche Cobas E Modular platform or the BioRad Bio-plex system.
Hepatitis B and C
Our screens for hepatitis B are the surface antigen and antibody IGG/IGM tests run on the Roche Cobas 6000 by immunoassay.
Our screen for hepatitis C is IgG / IgM antibody run on the Roche Cobas 6000 by immunoassay.
Can I find out more about HIV testing?
Questions about testing for HIV
The definitions below may be useful when reading these Questions about HIV:
Human Immunodeficiency Virus
something your body produces to fight an infection
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 healthcare professional with the patient present that gives an instant result
the container that Fettle uses to collect blood samples to send to the laboratory
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
a test or group of tests that are used to confirm the presence of a disease or infection (often done after a screening test)
a term used when a screening test has suggested the presence of infection but needs to be confirmed
a term that is used with more confidence when a test or group of tests confirms the presence of a disease or infection
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)
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)
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, Fettle uses a finger prick test and collects a small blood sample in a 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 after the HIV window period (4 weeks) - the time that it takes for an HIV infection to show up in tests.
How common are reactive results and how many of these are false positives?
False reactives are rare. Online STI testing services that we work in partnership with have recorded a false reactive rate of less than 0.5%.
What is the difference between a POCT and an HIV test with Fettle?
The HIV test that Fettle 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 Fettle’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 immunosorbent 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?
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 Fettle HIV test, you will be referred into clinic where you may be offered a further screening test (a POCT test that gives an instant result) as well as 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 confirmation of your result.
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: http://www.aidsmap.com/Sensitivity-and-specificity/page/1322984/
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.
What is a discordant result?
Fettle uses highly sensitive & specific diagnostic tests for HIV, Syphilis, Chlamydia, Gonorrhoea, Hepatitis B and Hepatitis C; 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 and Gonorrhoea to be wrong.
When Fettle refers you to a service for treatment for Chlamydia and 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.
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Is Fettle compliant with the General Data Protection Regulation?
SH:24, Fettle's parent service, 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.
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).