Taking into consideration that early infection usually doesn't cause symptoms, it is the most important to test blood on antibodies presence aimed against viruses. HIV antibodies usually do not reach measurable values during first three months after infection, but sometimes it is needed that even 6 months pass in order to have enough antibodies, which can be visible on standard blood testing. There are two basic tests on HIV: ELISA and Western Blot. If there is great possibility that person is infected, but both tests are negative, doctor can ask for test that will show virus presence in blood. In that case, it is need to repeat test again after some period, when there is bigger possibility that enough antibodies are created.
HIV detection in organism can be done using two methods:
- detecting virus itself, its genetic structure (PCR method)
- detecting specific antibodies on HIV in blood (Elisa test and Western-Blot test)
Using PCR method virus in organism can be detected right after infection, but this method is expensive and is not used on regular bases. Test, which is generally used is Elisa or screening test. This test detects antibodies in blood, but it have to be done not earlier than minimum 4-6 weeks after risk contact, even it is recommended to wait 3-6 months, because only then test can show HIV status with most certainty. During that period (window period) infected organism makes antibodies as answer of immune system, and those antibodies can be detected by test.
Test result can be:
- HIV negative (seronegative or no reactive)
- HIV positive (seropositive or reactive).
If result of Elisa test is positive, it means that person is HIV infected. As confirmation of this test new test is conducted (Western-Blot) and if it is positive, then person is HIV infected.