title: Two-step tuberculin skin testing of injection drug users recruited from community-based settings.
abstract: METHODS
  Cross-sectional study of drug users recruited from street-based settings in four US cities: Denver, Portland, Oakland and San Francisco.
  
  
  OBJECTIVE
  To evaluate responses to two-step tuberculin skin testing among HIV-positive and HIV-negative injection drug users.
  
  
  METHODS
  Subjects were recruited from existing studies of HIV and risk behaviors for tuberculin skin testing. Those with a negative initial tuberculin test were referred for a second skin test 1-3 weeks later. A positive tuberculin test was defined as > or = 10 mm, or > or = 5 mm if the subject was HIV-positive.
  
  
  RESULTS
  Of 997 persons receiving an initial tuberculin test, 13% had a positive response. Of 644 persons receiving a second tuberculin test, 8% had a positive response, with rates as high as 14% among those from Oakland and 12% among African Americans. HIV-positive subjects were less likely to have skin test responses > or = 10 mm on the initial test (P = 0.03), or increases between the initial and second test of > or = 10 mm (P = 0.06).
  
  
  CONCLUSIONS
  Boosting occurred in both HIV-positive and HIV-negative injection drug users. Two-step testing should be considered for this population, particularly those on whom repeat tuberculin testing will be performed.
authors.affiliation: Division of Epidemiology, University of Minnesota, Minneapolis 55424, USA. lifson@epivax.epi.umn.edu
authors.forename: A R
authors.initials: AR
authors.lastname: Lifson
authors.forename: S M
authors.initials: SM
authors.lastname: Grant
authors.forename: J
authors.initials: J
authors.lastname: Lorvick
authors.forename: F D
authors.initials: FD
authors.lastname: Pinto
authors.forename: H
authors.initials: H
authors.lastname: He
authors.forename: S
authors.initials: S
authors.lastname: Thompson
authors.forename: E G
authors.initials: EG
authors.lastname: Keudell
authors.forename: M J
authors.initials: MJ
authors.lastname: Stark
authors.forename: R E
authors.initials: RE
authors.lastname: Booth
authors.forename: J K
authors.initials: JK
authors.lastname: Watters
mesh_terms: D000328:Adult; D002140:California / Q000453:epidemiology; D003120:Colorado / Q000453:epidemiology; D003153:Community Health Services / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000453:epidemiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009922:Oregon / Q000453:epidemiology; D015995:Prevalence; D044469:Racial Groups; D012307:Risk Factors; D012309:Risk-Taking; D015819:Substance Abuse, Intravenous / Q000150:complications / Q000453:epidemiology*; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology