Table 3.

Diagnostic Assays Used for HIV Testing

HIV antibody tests
 EIAs, WB , IFAs
 Rapid EIAs available; can be performed on blood or saliva specimen
 Traditional HIV antibody testing has required positive EIA result, confirmed by positive WB (or IFA) result for HIV diagnosis
Combination HIV antigen and antibody (fourth-generation) tests
 Detects anti-HIV IgM and IgG antibodies and p24 antigen
 IgM and antigen detection components improve sensitivity for detecting primary HIV infection
 Not appropriate for HIV diagnosis in infants (age <18 months)
Nucleic acid amplification tests
 HIV DNA PCR; used only for infant diagnosis
 HIV RNA PCR and other assays; quantitative and qualitative; used for infant diagnosis and primary HIV infection diagnosis (quantitative assays also used for monitoring virologic response to antiretroviral therapy)
  • EIA=enzyme immunoassay; HIV=human immunodeficiency virus; IFA=immunofluorescent assay; PCR=polymerase chain reaction; WB=Western blot.

  • See Centers for Disease Control and Prevention (26) for additional information.