HIV testing

An HIV antibody test is usually done on a sample of your blood and shows if you have HIV. The test doesn't look for HIV itself, but for the antibodies to the virus. The body makes antibodies to fight infections, but antibodies made to fight HIV can't destroy the virus.

What a 'positive' HIV test result means

If you get a positive result it means:

• you're HIV positive; that is, you've been infected with HIV
• you can infect others if you have unsafe sex or share drug taking equipment such as needles, filters and so on.

A positive result doesn't say anything about how your health will be in the future. And it doesn't mean you have AIDS or will go on to develop AIDS.

If people know you have HIV, it might mean you'll come across hostility and prejudice.

What a 'negative' HIV test result means

If you get a negative result it means you're HIV negative; that is, you don't have HIV. But this is true only if the test was done at least three months after the last time you did something that put you at risk of getting HIV.

If you do something that puts you at risk of getting HIV and then get a negative test, it doesn't mean you can take risks in the future and stay uninfected. No-one should believe they're immune to HIV.

The window period

If you're infected with HIV, antibodies aren't made straight away. It can take weeks or months before they appear. This is called the window period and it usually lasts less than three months.

Because of the window period, if you want to know if you have HIV, you must wait three months before being tested; that's three months since the time you think you may have been infected. If you get the test done before then, then it can come back negative when really you are infected and very infectious. But because the antibodies to HIV haven't been made yet, this won't show up in your blood.

Trusting the test

HIV tests are very reliable. If a test result is positive, another two different tests are carried out on the blood to make sure the result is correct.

Whose test is it anyway?

An HIV test result is only true for the person whose blood is tested. It can be easy to hear of results given to friends, boyfriends and ex-boyfriends and be tempted to guess what that might mean for ourselves. But only by being tested yourself can you be sure whether you have HIV or not.

Studies show that quite a few men think they have HIV when they don't, or believe they're HIV negative when in fact they have the virus.