Use of laboratory tests and clinical symptoms for identification of primary HIV infection

AIDS. 2002 May 24;16(8):1119-29. doi: 10.1097/00002030-200205240-00005.


Objective: To determine the sensitivity and specificity of symptoms, three HIV-1 RNA assays, a p24 antigen EIA and a third-generation enzyme immunoassay (EIA) antibody test for diagnosis of primary HIV infection (PHI).

Design: Prospective cohort in a university research program.

Participants: Of 258 eligible persons screened for PHI, 40 had primary/early infection (22 preseroconversion, 18 within 6 months of seroconversion) and 218 did not. Seven participants with preseroconversion HIV-1 from a second center were added for evaluating laboratory tests.

Main outcome measure: PHI, defined as a negative or indeterminate antibody test with subsequent conversion. Symptom analysis also included persons with antibody conversion of less than 6 months' duration.

Results: The symptoms most strongly associated with PHI in multivariate analysis were fever [odds ratio (OR) 5.2; 95% confidence interval (CI) 2.3-11.7] and rash (OR 4.8; 95% CI 2.4-9.8). The sensitivity and specificity, respectively, for detecting preseroconversion HIV infection were: p24 antigen, 79% and 99%; third-generation EIA, 79% and 97%; HIV-1 RNA by branched chain DNA 100% and 95%; HIV-1 RNA by polymerase chain reaction 100% and 97%; HIV-1 RNA by transcription-mediated amplification testing, 100% and 98%. False-positive HIV-1 RNA tests were not reproducible and had values < 3000 copies/ml, while only one person with confirmed PHI was in this range.

Conclusions: Rash and fever indicated the highest risk of PHI. HIV-1 RNA tests are very sensitive for PHI but false-positive results occur. False-positive results can be reduced through duplicate testing and considering tests < 5000 copies/ml as indeterminate results requiring additional testing. p24 antigen was more specific than HIV-1 RNA testing but less sensitive.

Publication types

  • Clinical Trial
  • Evaluation Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Cohort Studies
  • Exanthema
  • False Positive Reactions
  • Female
  • Fever
  • HIV Antibodies / analysis
  • HIV Core Protein p24 / analysis
  • HIV Infections / diagnosis*
  • HIV Infections / physiopathology
  • HIV Seropositivity
  • HIV-1* / genetics
  • HIV-1* / immunology
  • HIV-1* / isolation & purification
  • Humans
  • Immunoenzyme Techniques / methods*
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • RNA, Viral / analysis*
  • Sensitivity and Specificity


  • HIV Antibodies
  • HIV Core Protein p24
  • RNA, Viral