Methods of diagnosis of PHI.
| Diagnostic test | Diagnostic method | Time from infection to detection |
|---|---|---|
| HIV antibody test | Venous blood; POC finger prick test; oral swab test; self-testing | 21 days (discordance in POC results strongly suggests PIH) |
| p24 antigen test | Venous blood sample fourth generation combo-antigen-antibody test | 14 days |
| RITA | Venous blood PHE | Up to 16 weeks from estimated date of infection |
| HIV RNA or DNA | Venous blood PCR | 7 days of infection |
PHI = primary HIV infection; PCR = polymerase chain reaction; PHE = Public Health England; POC = point of care; RITA = recent HIV test algorithm.