HIV1 p24 Antigen Neutralization

**Semantic type:** Laboratory Procedure

**Definition:** An assay used to confirm the presence of HIV1 p24 antigen in a blood sample. Following repeated positive results by a virus-specific enzyme immunosorbant assay, free antibodies specific for HIV1 p24 are added to the assay and should react with the viral protein and block a subsequent enzyme immunosorbant assay.