Which component incorporated into fourth-generation laboratory HIV assays shortened the diagnostic window period compared with third-generation antibody-only tests?
- A Detection of HIV p24 antigen together with antibodies ✓
- B Detection of gp120 antibody alone
- C Direct amplification of proviral DNA
- D Detection of HIV protease antigen
Correct answer: A. Detection of HIV p24 antigen together with antibodies
Explanation
Fourth-generation combination assays detect both HIV-1 and HIV-2 antibodies and the p24 capsid antigen, which appears in blood roughly a week before antibodies become detectable, reducing the window period to about 2 to 3 weeks. Proviral DNA PCR is used for infant diagnosis and special situations, not in standard screening assays, and protease antigen is not an assay target.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.