title: Use of the Abbott Architect HIV antigen/antibody assay in a low incidence population.
abstract: BACKGROUND
  With the availability of 4th generation HIV diagnostic tests which are capable of detecting acute infection, Iowa evaluated the 3rd and 4th generation HIV test and compared the performance of these products in a low incidence population.
  
  
  OBJECTIVE
  This study was conducted to evaluate the performance of an HIV antigen/antibody combination (4th generation) assay compared to an EIA 3rd generation assay.
  
  
  METHODS
  Over a 4 month period, 2037 specimens submitted for HIV screening were tested by Bio-Rad GS HIV-1/HIV-2 Plus O EIA and the Abbott Architect i1000SR HIV Ag/Ab Combo. The performance characteristics of sensitivity, specificity, positive predictive value and negative predictive value were determined.
  
  
  RESULTS
  Of the 2037 specimens tested, there were 13 (0.64%) true positives detected. None of the positive specimens were from patients in the acute phase of infection. The Abbott antigen/antibody combo assay had a sensitivity, specificity, positive-predictive value and negative predictive value of 100%, 99.85%, 81.25%, and 100% respectively. The Bio-Rad EIA assay had a sensitivity, specificity, positive-predictive value and negative predictive value of 100%, 99.80%, 76.47% and 100%, respectively. The EIA had four false positive results which tested negative by the antigen/antibody assay and western blot.
  
  
  CONCLUSIONS
  In a low-incidence state where early infections are less commonly encountered, the EIA assay and the antigen/antibody assay performed with near equivalency. The antigen/antibody assay had one less false positive result. While no patients were detected in the acute stage of infection, the use of the antigen/antibody assay presents the opportunity to detect an infected patient sooner and prevent transmission to others.
authors.affiliation: State Hygienic Laboratory at the University of Iowa, 2490 Crosspark Road, Coralville, IA 52241, United States.
authors.forename: Terry
authors.initials: T
authors.lastname: Dubravac
authors.affiliation: State Hygienic Laboratory at the University of Iowa, 2490 Crosspark Road, Coralville, IA 52241, United States.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Gahan
authors.affiliation: State Hygienic Laboratory at the University of Iowa, 2490 Crosspark Road, Coralville, IA 52241, United States. Electronic address: michael.pentella@state.ma.us.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Pentella
mesh_terms: D003955:Diagnostic Tests, Routine / Q000379:methods*; D015483:HIV Antibodies / Q000097:blood*; D015488:HIV Antigens / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis* / Q000453:epidemiology; D015497:HIV-1 / Q000276:immunology*; D015498:HIV-2 / Q000276:immunology*; D006801:Humans; D015994:Incidence; D007484:Iowa / Q000453:epidemiology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods
chemical_list: D015483:HIV Antibodies; D015488:HIV Antigens
keywords: HIV diagnostic testing