title: Clinical evaluation of the T-SPOT.TB test for patients with indeterminate results on the QuantiFERON TB-2G test.
abstract: OBJECTIVE
  To evaluate the clinical utility of the T-SPOT.TB test for patients with indeterminate results on the QFT-2G test.
  
  
  METHODS
  Forty patients (10.6%) showed indeterminate results among 378 patients who underwent QFT-2G test because active TB disease was clinically suspected. T-SPOT.TB test was performed for these 40 patients before the initiation of antituberculous treatment.
  
  
  RESULTS
  Forty patients (10.6%) were judged as showing indeterminate results on QFT-2G test because the positive control presented a lower IFN-gamma level. Elderly patients (68.2 versus 57.7) or immunocompromised patients receiving immunosuppressive treatments and patients with a decrease in lymphocyte count, serum protein and albumin were more frequently recognized in the patients with indeterminate results compared to those with determinate results on QFT-2G test. T-SPOT.TB test could clearly demonstrate the results in 26 of the 40 patients (65.0%) with indeterminate results of QFT-2G test; these were divided into six patients with positive results and 20 with negative results of T-SPOT.TB test. Elderly patients (73.5 versus 64.3) or patients with underlying diseases such as malignant disease and those receiving immunosuppressive treatment and patients with hyponutritional conditions were more frequently recognized in the patients with indeterminate results compared to patients with determinate results on both tests.
  
  
  CONCLUSIONS
  We think it may be necessary to introduce T-SPOT.TB test to increase the diagnostic rate of TB disease including latent tuberculosis infection because indeterminate results of QFT-2G test might be further decreased using T-SPOT.TB test. Although 14 patients showed indeterminate results on both tests, the lymphocytes of these patients may not possess functional cytokine production activity.
authors.affiliation: Division of Respiratory Diseases, Department of Medicine, Kawasaki Medical School, Kurashiki, Japan. yoshihiro@med.kawasaki-m.ac.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kobashi
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Sugiu
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ohue
authors.forename: Keiji
authors.initials: K
authors.lastname: Mouri
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Obase
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyashita
authors.forename: Mikio
authors.initials: M
authors.lastname: Oka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology
chemical_list: D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma