To perform an HIV antibody test one needs:

• HIV proteins, that is HIV antigens,
• a blood sample,
• and a gold Standard.

The latter is necessary because finding a reaction between the HIV proteins and antibodies present in the blood does not prove that the blood contains HIV antibodies, that is, antibodies specifically induced by HIV.

There is a very good reason for this. Antibodies directed against antigen other than the HIV proteins, may also react with the HIV proteins.

This so called cross-reactivity, is especially likely to happen when the sample is from AIDS patients and those at risk, since their blood is known to have antibodies against many infectious agents as well as auto-antibodies.

Because of this, the test specificity must be determined by using a gold standard, that is, by comparing the results of an antibody-antigen reaction with the ability to isolate HIV.

If there are such entities as HIV antibodies they will manifest if and only if it is also possible to simultaneously isolate HIV from the patients’ cultures.