A variety of tests for HIV are available, such as urine tests, blood tests, oral tests, and others. They look for the presence of antibodies to HIV (proteins that fight the infection). Regardless of the type of test used, a positive test result must be confirmed with an additional specific test before a diagnosis of HIV can be given.
Several tests for HIV are available. These include:
- Blood tests
- Urine tests
- Oral tests
- Rapid tests
- Home tests.
When HIV enters the body, it begins to attack certain white blood cells called T4 lymphocyte cells (helper cells). Your doctor may also call them CD4 cells. The immune system then produces antibodies to fight off the infection. Thus, the presence of HIV antibodies results from being infected with HIV. Although these antibodies are ineffective at destroying HIV, their presence is used to confirm an infection. HIV tests look for the presence of HIV antibodies; they do not test for the virus itself.
Several blood-based HIV tests are available:
- ELISA or EIA for initial screening
- Western blot to confirm the diagnosis
- Other, newer blood tests.
Screening Tests: ELISA or EIA HIV
HIV testing consists of an initial screening with two types of blood tests commonly used to detect an infection. The most commonly used initial blood test is an enzyme immune assay (EIA) or the enzyme-linked immunosorbent assay (ELISA) test. If EIA test results show a reaction, the test is repeated on the same blood sample.