title: Comparison of the sensitivity and specificity of two whole blood interferon-gamma assays for M. tuberculosis infection.
abstract: OBJECTIVE
  To compare the sensitivity and the specificity of the QuantiFERON-TB Gold (QFT-G) and QuantiFERON-TB Gold In Tube (QFT-GIT) diagnostic tests for Mycobacterium tuberculosis infection.
  
  
  METHODS
  One-hundred patients with culture and/or PCR confirmed M. tuberculosis infection and 168 volunteers with no risk factors for M. tuberculosis infection were tested to estimate sensitivity and specificity, respectively.
  
  
  RESULTS
  Analysis of data from the tuberculosis (TB) patients with valid results found the sensitivity of QFT-GIT (92.6%, 87/94) to be significantly higher than that for the QFT-G test (81.4%, 79/97; p=0.023). The specificity of both QFT-GIT and QFT-G was 98.8% (CI: 95.1%-99.8%) with 2 of the 160 low risk subjects with valid results for both tests being positive. Data analysis confirmed the manufacturer's recommended test cut-off as being optimal, but identified higher sensitivity could be obtained by using a lower cut-off, with only a moderate decrease in specificity.
  
  
  CONCLUSIONS
  The QFT-GIT test had enhanced sensitivity for detection of M. tuberculosis infection over the QFT-G test, whilst maintaining equivalent high specificity. The logistic benefits of the QFT-GIT test format, as well as its higher sensitivity, should enable enhanced TB control.
authors.affiliation: The Research Institute of Tuberculosis, 3-1-24, Matsuyama, Kiyose City, Tokyo 204-8533, Japan. harada@jata.or.jp
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Harada
authors.forename: Kazue
authors.initials: K
authors.lastname: Higuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiyama
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Kawabe
authors.forename: Akira
authors.initials: A
authors.lastname: Fujita
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Masahide
authors.initials: M
authors.lastname: Horiba
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mitarai
authors.forename: Makoto
authors.initials: M
authors.lastname: Yonemaru
authors.forename: Hideo
authors.initials: H
authors.lastname: Ogata
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Ariga
authors.forename: Atsuyuki
authors.initials: A
authors.lastname: Kurashima
authors.forename: Akihiko
authors.initials: A
authors.lastname: Wada
authors.forename: Mikio
authors.initials: M
authors.lastname: Takamori
authors.forename: Fumio
authors.initials: F
authors.lastname: Yamagishi
authors.forename: Kiminori
authors.initials: K
authors.lastname: Suzuki
authors.forename: Toru
authors.initials: T
authors.lastname: Mori
authors.forename: Nobukatsu
authors.initials: N
authors.lastname: Ishikawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology
chemical_list: D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma