title: Replacing clinic-based tests with home-use tests may increase HIV prevalence among Seattle men who have sex with men: evidence from a mathematical model.
abstract: BACKGROUND
  Home-use tests have potential to increase HIV testing but may increase the rate of false-negative tests and decrease linkage to HIV care. We sought to estimate the impact of replacing clinic-based testing with home-use tests on HIV prevalence among men who have sex with men (MSM) in Seattle, Washington.
  
  
  METHODS
  We adapted a deterministic, continuous-time model of HIV transmission dynamics parameterized using a 2003 random digit dial study of Seattle MSM. Test performance was based on the OraQuick In-Home HIV Test (OraSure Technologies, Inc, Bethlehem, PA) for home-use tests and, on an average, of antigen-antibody combination assays and nucleic acid amplification tests for clinic-based testing.
  
  
  RESULTS
  Based on observed levels of clinic-based testing, our baseline model predicted an equilibrium HIV prevalence of 18.6%. If all men replaced clinic-based testing with home-use tests, prevalence increased to 27.5% if home-use testing did not impact testing frequency and to 22.4% if home-use testing increased testing frequency 3-fold. Regardless of how much home-use testing increased testing frequency, any replacement of clinic-based testing with home-use testing increased prevalence. These increases in HIV prevalence were mostly caused by the relatively long window period of the currently approved test. If the window period of a home-use test were 2 months instead of 3 months, prevalence would decrease if all MSM replaced clinic-based testing with home-use tests and tested more than 2.6 times more frequently.
  
  
  CONCLUSIONS
  Our model suggests that if home-use HIV tests replace supplement clinic-based testing, HIV prevalence may increase among Seattle MSM, even if home-use tests result in increased testing.
authors: From the Departments of *Medicine, †Epidemiology, and ‡Global Health, University of Washington, Seattle, WA; and §HIV/STD Program, Public Health-Seattle & King County, Seattle, WA.
authors: David A
authors: DA
authors: Katz
authors: Susan L
authors: SL
authors: Cassels
authors: Joanne D
authors: JD
authors: Stekler
mesh_terms: D000328:Adult; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data*; D017280:Condoms / Q000706:statistics & numerical data; D005188:False Negative Reactions; D006679:HIV Seropositivity / Q000175:diagnosis*; D007722:Health Knowledge, Attitudes, Practice; D006297:Health Services Accessibility / Q000706:statistics & numerical data; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D008403:Mass Screening; D008962:Models, Theoretical; D021141:Nucleic Acid Amplification Techniques; D015995:Prevalence; D011933:Reagent Kits, Diagnostic; D018570:Risk Assessment; D012648:Self Care; D012725:Sexual Behavior / Q000706:statistics & numerical data; D014861:Washington / Q000453:epidemiology
chemical_list: D011933:Reagent Kits, Diagnostic