title: Specificity of the tuberculin skin test and the T-SPOT.TB assay among students in a low-tuberculosis incidence setting.
abstract: OBJECTIVE
  Interferon-γ release assays (IGRAs) are an important tool for detecting latent Mycobacterium tuberculosis infection (LTBI). Insufficient data exist about IGRA specificity in college health centers, most of which screen students for LTBI using the tuberculin skin test (TST).
  
  
  METHODS
  Students at a low-TB incidence college health center.
  
  
  METHODS
  TST and T-SPOT.TB were performed on prospectively recruited students. TB exposure risk was assessed using a questionnaire: Those at low risk were assumed to not have LTBI in order to calculate test specificity.
  
  
  RESULTS
  Of 184 students enrolled, 143 had results available for both TST and T-SPOT.TB. Agreement of the tests was 97% (kappa statistic 0.717; 95% confidence interval, 0.399-1.00). Among 124 low-risk students, specificity for TST and T-SPOT.TB were 98.4% and 100%, respectively.
  
  
  CONCLUSIONS
  T-SPOT.TB specificity was high among low-risk students. Additional studies such as cost-effectiveness analyses using T-SPOT.TB as a single or confirmatory test to TST are needed to contribute to LTBI screening policy decisions.
authors.affiliation: Dartmouth Medical School, Hanover, New Hampshire, USA. elizabeth.talbot@dartmouth.edu
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Talbot
authors.forename: Dawn
authors.initials: D
authors.lastname: Harland
authors.forename: Wendy
authors.initials: W
authors.lastname: Wieland-Alter
authors.forename: Sherry
authors.initials: S
authors.lastname: Burrer
authors.forename: Lisa V
authors.initials: LV
authors.lastname: Adams
mesh_terms: D005240:Feasibility Studies; D006801:Humans; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000097:blood / Q000175:diagnosis*; D009169:Mycobacterium tuberculosis / Q000276:immunology / Q000302:isolation & purification*; D013333:Student Health Services / Q000379:methods; D013334:Students / Q000706:statistics & numerical data; D014374:Tuberculin Test; D014495:Universities