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HIV / AIDS test - p24 antigen in the blood
Last reviewed: 23.04.2024
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Antigen p24 in serum is normally absent.
P24 antigen is the protein of the HIV nucleotide wall. The stage of primary manifestations after infection with HIV is a consequence of the onset of a replicative process. The p24 antigen appears in the blood 2 weeks after infection and can be detected by ELISA during 2 to 8 weeks. After 2 months from the onset of infection, p24 antigen disappears from the blood. Further in the clinical course of HIV infection, the second increase in the content of the p24 protein is noted. It falls on the period of the formation of AIDS.
Existing ELISA test systems for the detection of p24 antigen are used for early detection of HIV in blood donors and children, determining the prognosis of the course of the disease and monitoring the therapy. The ELISA method has a high analytical sensitivity, which makes it possible to detect HIV-1 antigen p24 in serum at concentrations of 5-10 pg / ml and less than 0.5 ng / ml of HIV-2, and specificity. However, it should be noted that the content of p24 antigen in the blood is subject to individual variations, which means that only 20-30% of patients can be identified with this study in the early period after infection.
Antibodies to the p24 antigen of the IgM and IgG classes in the blood appear starting from the 2nd week, reach a peak for 2-4 weeks and are kept at this level for different times - antibodies of the IgM class for several months, disappearing within a year after infection, and IgG antibodies can persist for years.
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