Diagnosis of HIV infection

HIV can't be diagnosed through a medical examination or via disease symptoms. Diagnosis is only possible on the detection of the HIV virus or antibodies in body fluids (e.g. blood). Normally the presence of antibodies is tested.

The diagnostic window:
It takes some weeks before sufficient quantities of antibodies exist in the blood for the test. This period from infection to proof of infection is called the diagnostic window. The period varies from person to person and is dependent on several factors (transmission path, quantity of transferred viruses, immune system etc.).

The diagnostic window can be reduced by an average of 3 weeks with the use of an antigen (virus) test or a combination of antigen and antibody tests. For most people the time taken between infection and diagnosis is 3 months but it may take 6 months before it is possible.



HIV infection and anti-body reaction
The green curve shows the concentration of the antibodies against the HIVs in the blood. The red line shows the virus concentration (antigen) in the HIV infected blood. HIV can diagnosed at the earliest after two weeks and the antibodies at the earliest 3 weeks later.