title: Performance evaluation of the point-of-care INSTI™ HIV-1/2 antibody test in early and established HIV infections.
abstract: The flow-through INSTI™ HIV-1/HIV-2 Rapid Antibody (INSTI) test is a 60s FDA-approved test for HIV-1 and HIV-2 antibody testing using whole blood and plasma.
  
  
  
  We evaluated the performance of INSTI using plasma and simulated whole blood specimens.
  
  
  
  INSTI's performance in plasma specimens from commercial seroconversion panels was assessed by estimating the relative sensitivity using a 50% cumulative frequency analysis and by comparing its performance with other FDA-approved rapid tests (RTs). INSTI was further evaluated using 320 HIV-1 plasma specimens collected during a cross-sectional study and with 107 HIV-1 and 24 HIV-2 simulated whole blood specimens. Sensitivity and specificity were calculated using 615 known HIV-1 group M/O and 80 HIV-2 (Western blot (WB)-positive), and 497 HIV-negative plasma specimens, respectively.
  
  
  
  In HIV-1 seroconversion panels, INSTI became reactive 9days before a positive WB. When compared to FDA-approved antibody-based lateral flow RTs, INSTI detected significantly more early infections. Among HIV-1-infected cross-sectional plasma samples, INSTI detected 23 (27%) of 85 Architect-positive/Multispot-negative or indeterminate specimens. For plasma specimens, the sensitivity was 99.84% for HIV-1 and 100% for HIV-2, and the specificity was 99.80%. Using simulated whole blood from seroconverters, INSTI performed similarly to plasma.
  
  
  
  INSTI performed significantly better than antibody-based lateral flow RTs during early stages of seroconversion. Sensitivity and specificity were within the manufacturer's reported ranges. Considering the observed test performance and the almost immediate results, INSTI is an accurate option to detect HIV-1/HIV-2 antibodies in point-of-care settings where lab testing is not feasible.
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Sarah
authors.initials: S
authors.lastname: Adams
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Laura
authors.initials: L
authors.lastname: Wesolowski
authors.affiliation: San Francisco Department of Public Health, San Francisco, CA, United States.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Cohen
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Peters
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: S Michele
authors.initials: SM
authors.lastname: Owen
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, United States. Electronic address: Svm6@cdc.gov.
authors.forename: Silvina
authors.initials: S
authors.lastname: Masciotra
mesh_terms: D015492:AIDS Serodiagnosis; D000465:Algorithms; D015153:Blotting, Western; D003430:Cross-Sectional Studies; D015483:HIV Antibodies / Q000097:blood* / Q000302:isolation & purification; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology; D015497:HIV-1 / Q000276:immunology; D015498:HIV-2 / Q000276:immunology; D006801:Humans; D008403:Mass Screening; D019095:Point-of-Care Systems; D012680:Sensitivity and Specificity
chemical_list: D015483:HIV Antibodies
keywords: CLIA-waived test; Early HIV-1 infections; HIV-1/2 rapid test; Whole blood testing