The most accurate and reliable diagnostic tool used regularly is lab tests that look for HIV antibodies and the p24 antigen.
They are “fourth-generation” tests, meaning that the technology used in them is more advanced than earlier tests.
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What Happens When a Person Gets HIV?
When a person gets HIV, their body makes antibodies against HIV.
In the weeks after being exposed to HIV, the immune system recognizes some of the virus’s parts and starts to make HIV antibodies to hurt, stop, or kill the virus. This time is called “seroconversion.” These antibodies will always be there.
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A structural protein called p24 is an HIV antigen. It makes up the majority of the HIV viral core.
During the short time between getting HIV and seroconversion, there are heightened levels of p24 in the blood, but then they go away. Since the p24 antigen is typically found several days before HIV antibodies, a test that can discover p24 has a somewhat shorter window period than a test that detects just antibodies.
The Newest Research and Information on HIV Tests
The plasma or serum is usually used for 4th-generation combination exams (2 components of blood, detached from whole blood using lab equipment). A needle takes a small amount of blood from a vein in your arm. In a machine in a lab, samples from several different people are analyzed simultaneously.
Like all screening tests, confirmatory tests must be done to check a reactive result, which is a preliminary positive test.
You may also hear these tests called ELISAs (enzyme-linked immunosorbent assay).
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Both the 1st-generation and 2nd-generation lab tests aren’t used any longer. The 3rd-generation lab test only looks for antibodies and isn’t recommended for use.
Some tests are also called “fifth-generation” tests. They find similar biomarkers but can also tell which samples are