HIV 1/2 ANTIGEN AND ANTIBODIES, FOURTH GENERATION WITH REFLEXES

LAB473

Reactive results will reflex to HIV confirmation send out. 

7 mL Red Top Tube

4.0 mL

Grossly hemolyzed or contaminated  samples

Set Up: Monday- Friday;  Report Available: 1 day

Non Reactive

The fourth generation HIV screening immunoassay detects serum antibodies directed against HIV-1, HIV-2 and the HIV-O variant (similar to the prior third generation HIV antibody screening assay), but also detects the HIV-1 p24 antigen which is present in the serum prior to seroconversion. The highest rate of HIV-1 transmission is during the period of p24 antigenemia (2-3 weeks after initial HIV infection) that precedes the development of detectable HIV antibodies (which may take 3-12 weeks after initial HIV infection to develop to detectable levels). The ability of this newer HIV screen to assay for the HIV-1 p24 antigen allows for the earlier detection of HIV-1 infection by days or weeks as compared to the prior HIV screening immunoassay, a clinically important factor in that initiation of antiretroviral therapy (ART) during the early stage of HIV-1 infection can benefit patients and reduce HIV-1 transmission. If the new fourth generation HIV screening immunoassay is repeatedly positive, then the next step in the HIV testing sequence is to perform the HIV Confirmation test that differentiates between the presence of HIV-1 and HIV-2 antibodies. HIV-2 diagnoses remain rare in the United States, primarily found in patients of West African descent. If there are discordant serum results between the new HIV screening immunoassay and the Multispot differential HIV-1/HIV-2 antibody assay, the same patient sample will be sent to Quest Diagnostics for the performance of HIV-1 qualitative RNA (nucleic acid) testing.