A patient comes to hospital with a history of sore throat, diarrhea and sexual contact 2 weeks before. The best investigation to rule out HIV is -
p24 antigen assay
ELISA
Western blot
Lymph node biopsy
The p24 antigen can be detected during window period, during which antibodies are not demonstrated in the serum. So, used for early detection. The p24 antigen appears within 2 weeks (average 16 days) after infection. So, it is the best investigation to rule out HIV among the options given above. Note: Nucleic acid test (NAT) is the earliest test to become positive, (even before p-24 antigen detection) Test Average period after infection when test becomes positive Nucleic acid test p24 antigen test Antibodies test 12 days 16 days 22 days Western blot: It detects the HIV antibodies. A lymph node biopsy can confirm a diagnosis of AIDS-related lymphoma.
Virology Pa-2 (RNA Virus Pa-1,2 & Miscellaneous Viruses)