title: The performance of the TBAg/PHA ratio in the diagnosis of active TB disease in immunocompromised patients.
abstract: OBJECTIVE
  The results of the T-SPOT.TB (T-SPOT) assay are reduced in immunocompromised patients with active tuberculosis (ATB), and it is difficult using T-SPOT results to distinguish ATB from latent tuberculosis infection (LTBI) in this condition. The aim of this study was to determine the performance of the TBAg/PHA ratio in T-SPOT assay in the diagnosis of ATB in immunocompromised patients.
  
  
  METHODS
  One hundred and forty three immunocompromised ATB patients and 124 LTBI individuals were diagnosed according to conventional tests and T-SPOT assay.
  
  
  RESULTS
  The results of T-SPOT assay are of no value in the diagnosis of ATB in immunocompromised patients. However, the number of phytohaemagglutinin (PHA) spot-forming cells (sfc) in T-SPOT assay was substantially decreased in immunocompromised ATB patients compared with that in LTBI individuals. Receiver operating characteristic (ROC) analysis revealed that a further calculation of the TBAg/PHA ratio (the larger of the ESAT-6/PHA and CFP-10/PHA) showed a better performance in distinguishing these two diseases. Using the threshold value of 0.316, the sensitivity and specificity for distinguishing immunocompromised ATB patients from LTBI individuals were respectively 79.21 and 94.05%.
  
  
  CONCLUSIONS
  Our findings suggest that the TBAg/PHA ratio might have some significance for the diagnosis of TB disease in immunocompromised patients.
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Munyemana Jean
authors.initials: MJ
authors.lastname: Bosco
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Hou
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Lie
authors.initials: L
authors.lastname: Mao
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Kreeti Devi
authors.initials: KD
authors.lastname: Ramroop
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Mao
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Electronic address: zysun@tjh.tjmu.edu.cn.
authors.forename: Ziyong
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Electronic address: fengwang@tjh.tjmu.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis*; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009161:Mycobacterium / Q000276:immunology*; D010835:Phytohemagglutinins / Q000032:analysis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D010835:Phytohemagglutinins
keywords: T-SPOT; TBAg/PHA ratio; active TB; immunocompromised patients