HIV testing is carried out to check the presence of antibodies (proteins that fight against infection) produced against HIV. They are used to detect the presence of the HIV in serum, saliva or urine. There are a large number of HIV testing techniques available for the same. The different types of tests included are:

• HIV blood tests
• Urine HIV test
• Oral HIV test
• Rapid HIV test
• HIV home tests.

When HIV enters the body, in the beginning it attacks the white blood cells (WBCs) called T4 lymphocyte cells (helper cells). Most doctors also refer to them as CD4 cells. The immune system in our body is responsible for the production of antibodies to fight against the infection. Thus, the presence of the HIV antibodies in our body is there as a result of HIV infection. Even though their presence doesn’t effect or destroy the HIV but their presence confirms the presence of HIV infection in the body of the victim. Thus, the thorough HIV testing techniques check the presence of HIV antibodies; and not that of the virus present.

The various types of HIV blood tests available are:

• ELISA or EIA for initial screening
• Western blot to confirm the diagnosis
• Other new blood tests.

HIV Blood Tests for Screening: ELISA or EIA HIV
HIV testing in this case consists of an initial screening in order to detect HIV infection. The most common type of test is the enzyme immune assay (EIA) or the enzyme-linked immunosorbent assay (ELISA) test. If in case the EIA test results show some kind of reaction, then in that case the test is repeated on the same blood sample. If the sample again shows the same results the second HIV blood test, such as the Western blot is carried out. It is more specific and tells the difference between HIV antibodies and other antibodies which react to the EIA and may cause false-positive results (i.e. the results which are not actually positive but appear to be so in the tests).

Apart from the EIA or ELISA and Western blot, other new HIV blood tests include:

• Radioimmunoprecipitation assay (RIPA): A confirmatory HIV blood test that is used when antibody levels are very low or difficult to detect.
• Dot-blot immunobinding assay: it is economic and may be used as an alternative to EIA or Western blot.
• Immunoflourescence assay: it is not commonly used and is used to check for the false positive EIA tests.
• Nucleic acid testing: A rarely available HIV blood test that is used to solve an initial indeterminate Western blot result.
• Polymerase chain reaction (PCR): it is a specialized HIV blood test that looks for HIV genetic information. It is comparatively costly and labor-intensive, but can detect the virus even in someone who is recently infected.

Urine and oral-fluid HIV testing serve as an alternative for the above stated tests.

• Urine HIV Test
  A urine HIV test is not as appropriate or sensitive as a blood test. The urine tests include an EIA and a Western blot test, which confirms EIA results.
• Oral HIV Test
  Fluid is taken from inside the mouth (saliva) and analyzed using an EIA test and followed by Western blot test, if necessary. This is carried out at many HIV testing locations.
• Rapid HIV Test
  The rapid HIV blood test is believed to be similar to EIA in accuracy. As is the case with all the screening tests (including the EIA), a positive test result is further confirmed with a specific test for diagnosis.
• HIV Home Tests
  Some kits are available in the markets which are used for HIV testing and the procedure involves pricking the finger, placing blood on specially treated card, which is then mailed for testing at a licensed laboratory. Customers are provided with an identification number to use. Mostly the results for the same are inappropriate.

One should not be shy or afraid of getting the HIV testing done as only after the test is carried out and HIV is diagnosed one can begin with the treatment.