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Testing for HIV

a test tube

People can live with HIV for years before having any symptoms. The only way to be sure is to have an HIV test. Find out where to test and how the test will be carried out.

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What is the test?

A blood test is the usual way HIV is detected. An HIV test can work by detecting:

  • antibodies (made by the body to try to fight HIV) or
  • antigens (a protein found in the HIV cell)
  • both antibodies and antigens.

Antigens are present in large quantities in the early weeks after infection and then stop being detectable, whereas antibodies can take up to 12 weeks to be detectable.

If no sign of infection is found the test is ‘negative’.

If infection is found the test is ‘positive’.

Someone who tests ‘positive’ has their blood tested a second time to be absolutely sure the result is accurate.

How long does it take for HIV to show up in a test?

Signs of HIV infection can’t be detected in the blood immediately. It usually happens within four weeks of infection (sometimes longer).

Different tests take different lengths of time before they can detect a recent infection.

If your risk was in the last three months, tell the person testing you as it may affect the type of test they use.

If your risk was recent the testing centre will probably advise you to have a test immediately, followed by a second one a few weeks later (this will pick up any recent infection the first test might have missed).

Very occasionally it can take up to three months for antibodies to appear in the blood, so an HIV negative result is only totally accurate if three months have passed between the test and the last time a risk was taken. However, a negative result four to eight weeks after taking a risk is a very good sign that HIV infection hasn’t happened. But to be absolutely sure another test should be taken around eight weeks later; the testing centre will advise you.

I’ve taken a risk - is there any way to prevent HIV infection now?

If the risk of HIV was taken in the last 72 hours it is possible to take PEP (Post-exposure Prophylaxis) to help stop an infection happening.

Where to test for HIV:

HIV tests are available free and confidentially from:

  • sexual health clinics
  • HIV testing centres such as Terrence Higgins Trust Fastest centres (where rapid tests are available)
  • a GP /family doctor.

You can also test at home by ordering a free postal test kit.

Do I have to pay for HIV testing?

You will not have to pay if you test with your GP, an NHS sexual health clinic or a testing centre such as Terrence Higgins Trust Fastest centres. Free home postal testing kits are also available from some places.

If you test at a private clinics you will have to pay. You can also buy home testing kits online instead of ordering a free one.

Use our Service Finder tool to find your local sexual health clinic or a Fastest Centre.

I’m worried about testing positive - can I put off HIV testing for now?

Avoiding a test now doesn’t make HIV go away but risks you finding out later when the virus has done a lot of damage and when HIV drugs may not work as well. HIV-related deaths in Britain now tend to happen to people who went undiagnosed and untreated for too long.

Also, if you know you have HIV you can take steps to protect others. If you have HIV but don’t know, you could be passing it on without realising.

There is a lot of support for people who test positive – you don’t have to face it on your own.

Finally, if you’re not a British citizen but are applying to stay in the UK, your HIV test result will not count against you, whatever the result.

Testing positive can save your life and add years to it.

Why test?

It’s never a good idea to be unsure of your HIV status. Testing puts you in control and, thanks to treatment, could stop you from getting seriously ill and even save your life.

Perhaps your HIV status is not what you think it is. A test will let you know and if you have a ‘rapid HIV test’ you don’t have to wait days for a result.

A test at least once a year is a good idea for people who have more than one sexual partner.

Testing at the start of a relationship as part of a full sexual health check-up also makes sense, especially if you plan on not using condoms.

After unprotected sex that could have put you at risk of HIV you should always take a test.

Remember - a negative test result in the past is no longer accurate if you’ve taken risks since.

What to expect at the clinic

Although you can now test at home, most people take HIV tests at a sexual health clinic, their family doctor or a testing centre such as Terrence Higgins Trust’s Fastest clinics.

The test is free, confidential and voluntary: you cannot be (and should not feel) forced to test. It should involve a brief chat first to discuss why you’ve decided to test, what risks you may have taken and when, and what kind of HIV test is the most appropriate based on this information.

You should have explained to you how the test will work, what the possible results mean and be asked how you would react to whatever result you get.

Blood will be taken either from your arm or, if you’re having a rapid HIV test, from a finger prick blood sample. The blood sample from your arm is then sent to a lab.

A finger prick rapid test will give you a result within minutes.

A blood sample from your arm is sent to a lab with the results ready within a day or up to a week later.

Testing at home

Testing at home is now an option. After receiving your test kit, you collect a sample of blood from your finger, then post your sample to a laboratory. A week or so later they will contact you about your result.

There are also oral HIV tests that get a result from saliva (antibodies are in the spit of an infected person but this doesn’t mean you can catch HIV from saliva; you can’t). Some postal testing schemes offer saliva tests.

How will I find out my results?

If you test in a clinic or testing centre and they take blood from your arm you might get your result later that day, in a day or so, or possibly up to a week or so later.

If you have a rapid test where blood is taken from your finger, then it will give a result within a minute (some tests take up to 20 minutes).

If getting your result quickly is important, call ahead and ask if they offer rapid tests or how soon results are ready.

If you test in a clinic, positive test results are not given by post, text or over the phone but in person.

If you use a home testing service, negative results are sent by text. If there’s a problem with your sample or the result is positive, you’ll be contacted by phone, or you might have the option of logging into a secure online system to get your result.

What should I do if my HIV test is positive?

Following a positive result you’ll have a longer talk about what happens next, what support is available and arrangements will be made to see an HIV specialist who will take care of your health.

Support groups, counsellors and online advice from myHIV and THT Direct on 0808 802 1221 are all available to help you get through this period.

HIV treatment is now so effective and easy to take that there’s much less reason why a positive result should be feared like it was in the past.

If someone has HIV they can now expect to enjoy a normal lifespan, as long as they test and start treatment early - before HIV damages their immune system.

Will the results of my HIV test be kept private?

Whatever your result, if you test at a clinic or testing centre it will remain confidential.

No-one will be told: not your employer, the immigration authorities, your family or partner (although the testing centre can support you if you decide to tell your partner).

No-one should be told your result unless you agree.

If you test in a clinic or testing centre, your family doctor won’t be told (unless he/she referred you by letter for the test).

There is no list of people with HIV kept by the authorities.

Remember: if you test with your family doctor this will go on your GP notes.

If I test positive for HIV, does that mean I have AIDS?

Remember, there is no such thing as an ‘AIDS test’.

Testing positive doesn’t mean you have AIDS or will get it, just that you have HIV.

With today’s effective HIV drugs someone who tests early and starts treatment in time can live a long, healthy and happy life.

HIV self testing ››

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The Information Standard: Certified member

This article was last reviewed on 26/8/2015 by T. Kelaart

Date due for the next review: 25/8/2018

Content Author: Richard Scholey

Current Owner: Health Promotion

More information:

BASHH. BASHH Statement on HIV window period.  2010. 

British HIV Association, British Association of Sexual Health and HIV, UK National Guidelines for HIV Testing 2008, British Infection Society, September 2008.

NAM. HIV testing, Aidsmap 

NAM. Types of test, Aidsmap

NAM. Home sampling and home testing, Aidsmap

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