title: Risk factors for false-negative T-SPOT.TB assay results in patients with pulmonary and extra-pulmonary TB.
abstract: OBJECTIVE
  To investigate the risk factors for false-negative T-SPOT.TB results in patients with pulmonary TB (PTB) and extra-pulmonary TB (EPTB).
  
  
  METHODS
  Patients with suspected TB who underwent valid T-SPOT.TB tests were prospectively enrolled at Beijing Chest Hospital between November 2012 and November 2013. Basic characters and clinical laboratory findings were compared between true-positive and false-negative T-SPOT.TB groups.
  
  
  RESULTS
  Of 1928 suspected TB patients, 774 (530 PTB and 244 EPTB) microbiologically/histopathogenically-confirmed patients (636 culture-confirmed) were analyzed. Forty-six PTB patients (8.7%) and 32 EPTB patients (13.1%) had negative T-SPOT.TB results. Multivariate analysis showed that increased age [odds radio (OR) 2.26, 95% confidence interval (CI) 1.11-4.58], over-weight (BMI ≥ 25 kg/m(2), OR 2.43, 95% CI 1.05-5.63), and a longer period of illness before hospitalization (>6 months, OR 2.46, 95% CI 1.24-4.92) were independent risk factors for false-negative T-SPOT.TB results in PTB patients. In EPTB patients, increased age (OR 2.42, 95% CI 1.09-5.35) also showed an independent association with false-negative T-SPOT.TB results.
  
  
  CONCLUSIONS
  Careful interpretation of negative T-SPOT.TB results is necessary in older patients with suspected PTB or EPTB, and in PTB patients who are over-weight or have had longer periods of illness before hospitalization.
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Pan
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Jia
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Huishan
authors.initials: H
authors.lastname: Sun
authors.affiliation: Tuberculosis Department, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, China.
authors.forename: Mengqiu
authors.initials: M
authors.lastname: Gao
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Fengjiao
authors.initials: F
authors.lastname: Du
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Aiying
authors.initials: A
authors.lastname: Xing
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Boping
authors.initials: B
authors.lastname: Du
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Wei
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Shuxiang
authors.initials: S
authors.lastname: Gu
authors.affiliation: Beijing Chest Hospital, Capital Medical University, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China. Electronic address: zzd417@163.com.
authors.forename: Zongde
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002681:China; D058501:Enzyme-Linked Immunospot Assay; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D050177:Overweight; D011446:Prospective Studies; D012307:Risk Factors; D014376:Tuberculosis / Q000175:diagnosis*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D007371:Interferon-gamma
keywords: Extra-pulmonary TB; False-negative; Pulmonary TB; Risk factor; T-SPOT.TB