title: Prospective head-to-head study comparing 2 commercial interferon gamma release assays for the diagnosis of tuberculous uveitis.
abstract: OBJECTIVE
  To perform a head-to-head comparison of 2 commercially available interferon-gamma release assays, QuantiFERON-TB Gold In-Tube (Cellestis, Chadstone, Victoria, Australia) and T-SPOT.TB (Oxford Immunotech, Abingdon, Oxfordshire, UK), in the diagnosis of tuberculous uveitis.
  
  
  METHODS
  Prospective cohort to study diagnostic accuracy.
  
  
  METHODS
  We recruited consecutive new patients who presented with uveitis to a tertiary institution over a 2-year period. All patients underwent complete ocular examination and systemic evaluation, including T-SPOT.TB, QuantiFERON-TB Gold In-Tube, and tuberculin skin test. Patients were followed-up for a minimum of 1 year after completion of antituberculous therapy where indicated. The main outcome measures were the sensitivity, specificity and accuracy of each test, estimated using Bayesian latent class analysis (presented with 95% Bayesian credible intervals) (Crl). Prior information was obtained from published meta-analyses for diagnostic tests: QuantiFERON Gold In-Tube sensitivity (0.64, 0.59-0.69) and specificity (0.99, 0.99-1.00); T-SPOT. tuberculosis sensitivity (0.50, 0.33-0.67) and specificity (0.91, 0.88-0.93).
  
  
  RESULTS
  From our study in patients with uveitis, QuantiFERON-TB Gold In-Tube was more specific but slightly less sensitive (sensitivity: 0.64, 0.60-0.69; specificity: 0.995, 0.988-0.999) than T-SPOT.TB (sensitivity: 0.67, 0.60-0.74; specificity: 0.91, 0.88-0.93). However, QuantiFERON Gold In-Tube was significantly more accurate in identifying true-positive tuberculous uveitis cases than was T-SPOT.TB among discordant cases (QuantiFERON Gold In-Tube positive 98% vs T-SPOT.TB positive 76%; ratio 1.28, 95% Crl: 1.11-1.72, ie, 95% Crl >1.0, statistically significant).
  
  
  CONCLUSIONS
  Based on statistical decision theory, our head-to-head study suggests that QuantiFERON-TB Gold In-Tube is the first-line test that should be performed in preference to T-SPOT.TB (and the tuberculin skin test) for diagnosing tuberculous uveitis.
authors: Singapore National Eye Centre, Singapore; Singapore Eye Research Institute, Singapore.
authors: Marcus
authors: M
authors: Ang
authors: Singapore Eye Research Institute, Singapore; Department of Ophthalmology, National University of Singapore, Singapore.
authors: Wan Ling
authors: WL
authors: Wong
authors: Singapore National Eye Centre, Singapore.
authors: Sieh Yean
authors: SY
authors: Kiew
authors: Singapore Eye Research Institute, Singapore; Department of Statistics and Applied Probability, National University of Singapore, Singapore.
authors: Xiang
authors: X
authors: Li
authors: Singapore National Eye Centre, Singapore; Singapore Eye Research Institute, Singapore; Department of Ophthalmology, National University of Singapore, Singapore; Duke-National University of Singapore Graduate Medical School, Singapore. Electronic address: chee.soon.phaik@snec.com.sg.
authors: Soon-Phaik
authors: SP
authors: Chee
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D059425:Interferon-gamma Release Tests; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D011237:Predictive Value of Tests; D011239:Prednisolone / Q000627:therapeutic use; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology; D014374:Tuberculin Test; D014392:Tuberculosis, Ocular / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D014605:Uveitis / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D005938:Glucocorticoids; D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma; D011239:Prednisolone