How does the HIV test work?

Lab test using a blood sample

We will ask you to provide a few drops of blood in a sample tube. We will usually complete three different tests on your sample. The first test is very sensitive so that it does not miss any HIV infection. If the first test is ‘reactive’ then two more tests are completed if there is enough blood in the sample.

‘Reactive’ means that there may be HIV antibodies or the HIV virus in your blood. We need to do more tests to make sure that this result is correct.

'Non-reactive' means that there are no HIV antibodies in your blood.

If all three tests are positive, then we are able to make a diagnosis of HIV infection.

Insti test using a blood spot

The Insti test uses a small amount of blood taken from a finger prick. It will give you an instant result.

If you have a reactive result, we will ask you to go to a clinic to give another blood sample so that they can check your result over three tests. If you do receive a reactive result, one of our clinicians will be on hand to talk you through this process.

Find out more about the accuracy of STI tests and the recommended 'window period' before testing.


Last updated at: 24 August 2022