title: Costs and outcomes of laboratory diagnostic algorithms for the detection of HIV.
abstract: BACKGROUND
  An alternative HIV testing algorithm, designed to improve the detection of acute and early infections and differentiate between HIV-1 and HIV-2 antibodies, has been developed by the Centers for Disease Control and Prevention and the Association of Public Health Laboratories. While it promises greater sensitivity, it also raises concerns about costs.
  
  
  OBJECTIVE
  We sought to compare the most commonly used algorithm which was developed in 1989, a third-generation (3G) immunoassay (IA) and Western blot confirmatory test, to a newer algorithm. The new algorithm includes either a 3G or a fourth-generation (4G) initial IA, followed by confirmatory testing with a HIV-1/HIV-2 differentiation IA and, if needed, a nucleic acid amplification test (NAT).
  
  
  METHODS
  We conducted an analysis of HIV testing costs from the perspective of the laboratory, and classified costs according to IA testing volume. We developed a decision analytic model, populated with cost data from 17 laboratories and published assay performance data, to compare the cost-effectiveness of the testing algorithms for a cohort of 30,000 specimens with a 1% HIV prevalence and 0.1% acute HIV infection prevalence.
  
  
  RESULTS
  Costs were lower in high-volume laboratories regardless of testing algorithm. For specimens confirmed positive for HIV antibody, the alternative algorithm (IA, Multispot) was less costly than the current algorithm (IA, WB); however, there was wide variation in reported testing costs. For our cohort, the alternative algorithm initiated with a 3G IA and 4G IA identified 15 and 25 more HIV infections, respectively, than the 1989 algorithm. In medium-volume laboratories, the 1989 algorithm was more costly and less effective than the alternative algorithm with a 3G IA; in high-volume laboratories, the alternative algorithm with 3G IA costs $162 more per infection detected. The alternative algorithm with 4G instead of 3G incurred an additional cost of $14,400 and $4865 in medium- and high-volume labs, respectively.
  
  
  CONCLUSIONS
  HIV testing costs varied with IA testing volumes. The additional cost of 4G over 3G IA might be justified by the additional cases of HIV detected and transmissions averted due to earlier detection.
  
  
  CONCLUSIONS
  The alternative HIV testing algorithm compares favorably to the 1989 algorithm in terms of cost and effectiveness.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States. Electronic address: ash2@cdc.gov.
authors.forename: Angela B
authors.initials: AB
authors.lastname: Hutchinson
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Steven F
authors.initials: SF
authors.lastname: Ethridge
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Wesolowski
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Ram K
authors.initials: RK
authors.lastname: Shrestha
authors.affiliation: State Hygienic Laboratory, University of Iowa, Iowa City, Iowa, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Pentella
authors.affiliation: Florida Bureau of Public Health Laboratories, Jacksonville, FL, United States.
authors.forename: Berry
authors.initials: B
authors.lastname: Bennett
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Farnham
authors.affiliation: Wadsworth Center, New York State Department of Health, Albany, NY, United States.
authors.forename: Timothy
authors.initials: T
authors.lastname: Sullivan
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Pragna
authors.initials: P
authors.lastname: Patel
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA, United States.
authors.forename: Bernard M
authors.initials: BM
authors.lastname: Branson
mesh_terms: D000465:Algorithms; D003362:Cost-Benefit Analysis; D003955:Diagnostic Tests, Routine / Q000191:economics* / Q000379:methods*; D042241:Early Diagnosis; D015658:HIV Infections / Q000175:diagnosis* / Q000191:economics* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000276:immunology; D015498:HIV-2 / Q000145:classification / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000191:economics / Q000379:methods; D021141:Nucleic Acid Amplification Techniques / Q000191:economics / Q000379:methods; D012680:Sensitivity and Specificity
keywords: Cost-effectiveness; Costs; HIV testing algorithms