HIV Testing Methods
Though there are several different types of tests available to screen for HIV. All are extremely accurate, providing up to 99 percent accuracy with their test results, though some methods are much more expensive than others and as such aren't used as often.
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Antibody Tests
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Antibody tests are the most commonly used screening tools to diagnose HIV. They come in several different varieties, some working together with others. Instead of looking for the HIV virus itself, they look for HIV-specific antibodies in the blood.
ELISA
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Enzyme-linked immunosorbent assay, or ELISA, is generally the first blood test given for HIV testing. It is used as a screening tool and can be up to 99-percent accurate at detecting antibodies which can indicate HIV infections, though the antibodies that it detects can also be caused by other infections as well (resulting in occasional false positives.)
Western Blot
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If a person tests positive on an ELISA test, a Western Blot is used in order to confirm the result. This test checks for HIV-specific antibodies, so a positive result is considered to be a definite indication of HIV infection.
Antigen Tests
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The antigen test looks for p24, a protein unique to HIV. This test was originally used to screen blood that was donated, but it was found to be somewhat unreliable because of its low sensitivity. Because of this, antigen tests are not used as commonly as they once were.
Oral Swab Tests
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Two types of oral swab tests exist, the OraQuick test and the OraSure. Both test for the presence of HIV indicators in saliva. OralQuick tests give results in around 20 minutes, but are considered to be inaccurate enough that they require follow-up testing for confirmation. OralSure tests are considered to be as accurate as blood tests, but require 2 weeks for result processing.
Nucleic Acid Tests
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Nucleic acid tests are incredibly reliable, as they test for the presence of the actual genetic material of HIV in a person's body. These are the most expensive types of HIV tests, however, and as such are generally not considered a viable option for mass screening purposes.
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