P24 is a target for the immune system, and antibodies against p24 are used in diagnostic tests to detect the presence of HIV antibodies. Fourth-generation HIV immunoassays detect viral p24 protein in the blood and patient antibodies against the virus.

One distinctive HIV antigen is a viral protein called p24, a structural protein that makes up most of the HIV viral core, or 'capsid'. High levels of p24 are present in the blood serum of newly infected individuals during the short period between infection and seroconversion, making p24 antigen assays useful in diagnosing primary HIV infection.

The p24 antigen test detects the presence of the p24 protein of HIV (also known as CA), the capsid protein of the virus. Monoclonal antibodies specific to the p24 protein are mixed with the person's blood.

Despite major advances in HIV testing, early detection of infection at the point of care (PoC) remains a key challenge. While rapid antibody PoC and laboratory-based nucleic acid amplification tests dominate the diagnostics market, the viral capsid protein p24 is recognized as an alternative early virological biomarker of infection.

The p24 test may be used to detect early HIV infection and to screen donated blood for HIV. Since p24 levels rise and fall with HIV levels, the test may also be used to monitor anti-HIV therapy and to evaluate disease progression.

Mar 25, 2025 · There are different types of HIV tests to detect the virus at various stages of infection. HIV Screening Tests. HIV-1/2 Antigen and Antibodies Test (4th Generation Test) Detects both HIV antibodies and the p24 antigen; Can identify HIV as early as 18–45 days after exposure; HIV Antibody Test (Rapid HIV Test) Detects HIV antibodies in oral fluid

In these tests the antigen being tested is a major HIV protein called p24. p24 (short for protein 24) is produced 2–3 weeks after infection and before antibodies are produced. p24 levels are only detectable for the next 1–2 months.

We demonstrate that human immunodeficiency virus (HIV) gag p24 protein is more readily detected in gut and lymph node tissues than in blood CD4 + T cells and correlates better with CD4 count during antiretroviral therapy (ART). Gut p24 levels also measurably decline with ART in natural controllers.

HIV antigen (p24 antigen) testing was approved for use for testing blood donors in 1996. As per Figure 12.1, finding the presence of an identifiable HIV antigen was a significant advance, as p24 antigen could be identified in the blood of infected donors earlier than anti-HIV.

Antigen p24 is a protein found in human immunodeficiency virus (HIV). This test is used to evaluate and manage HIV infection[1][2] or its more advanced stage, acquired immune deficiency syndrome (AIDS)[3][4][5].