Table 1.

Methods of diagnosis of PHI.

Diagnostic testDiagnostic methodTime from infection to detection
HIV antibody testVenous blood; POC finger prick test; oral swab test; self-testing21 days (discordance in POC results strongly suggests PIH)
p24 antigen testVenous blood sample fourth generation combo-antigen-antibody test14 days
RITAVenous blood PHEUp to 16 weeks from estimated date of infection
HIV RNA or DNAVenous blood PCR7 days of infection
  • PHI = primary HIV infection; PCR = polymerase chain reaction; PHE = Public Health England; POC = point of care; RITA = recent HIV test algorithm.