These are the preferred screening tests to detect HIV-1 antigen (p24), and IgM/IgG antibodies against HIV-1 and HIV-2. Currently, there are seven FDA-approved combined antigen/antibody tests available identified by the CDC.
- Six of these assays are CLIA rated as moderately complex and one is rated high complexity.
- All are able to detect the presence of HIV-1 and HIV-2 but only two differentiate them in the report.
- All tests detect the presence of p24, IgM, and IgG. Some manufacturers include the detection of HIV-1 Group O.
- Most of these assays are recommended for adults as well as pregnant patients, adolescents, and children as young as two years old.
- The volume of sample varies from as small as 39 µL to 350 µL.
- The run times for these assays vary from less than thirty minutes to more than three hours.
- A CDC study found that 99% of these tests are positive at 44.3 days after exposure while only 50% are positive at 17.8 days. Generally, the window period is considered 45 days.
