Application Of T-SPOT.TB In The Diagnosis Of Pulmonary Tuberculosis

Backgroud and objective：Tuberculosis is a kind of infectious bacterial disease causedby Mycobacterium tuberculosis．In recently years，incidence of tuberculosis has risedbecause of increasing incidences of HIV infection，international immigration and drugresistance MTB．To now，about2billion people have infected with MTB worldwide，20million patients have active pulmonary tuberculosis，and there are8million new patientswith tuberculosis yearly．Annually，3million patients (0.13million chineses) died of TB．InChina, among550milion patients infected with MTB，4.5milion patients have activepulmonary tuberculosis, which has caused high-burden．This severe condition urged us topay attention to the diagnosis and treatment of TB．But traditional diagnostic methods for TBhave lower sensitivity and worser specificity．In recent years, T-SPOT.TB was found anddeveloped gradually, which is a kind of new diagnostic methods for TB and based onthe response of MTB antigen-specific T cells．In this study, we discussed application ofT-SPOT.TB in the diagnosis of TB.Methods：We designed a prospective study enrolling90patients with suspected TB,who were admitted in The Second Hospital of Jilin University from September2011toMarch2012．We assessed the value of peripheral blood T-SPOT.TB assay for the diagnosisof active tuberculosis with comparing T-SPOT.TB test results and final clinical diagnosis inroutine clinical practice. To evaluate the application of T.SPOT-TB in the diagnosis ofpulmonary tuberculosis by detecting IFN-gamma-secreting T cells, we analyzed sensitivity、specificity、positive predictive value、negative predictive value、positive likelihood ratio、negative likelihood ratio of T.SPOT-TB．Among patients who diagnosed tuberculosis，wecompared the positive rate of T-SPOT.TB assay，acid-fast staining of sputamentum，tuberculosis antibody with ELISA assay，hisopathology diagnosis，and combination ofT-SPOT.TB assay and hisopathology diagnosis.Results：Among all90patients, sensitivity of T-SPOT.TB assay for active tuberculosiswas86.4％(19/22)， specificity was72.1％(44/61)，negative predictive value was93.6％， positive predictive value was52.8％，negative likelihood ratio was0.19，and positivelikelihood ratio was2.89．In52patients with non-serous cavity effusion，sensitivity ofT-SPOT.TB was91.7％(11/12)，specificity was85％(34/40)，negative predictive value was97.1％，positive predictive value was64.7％，negative likelihood ratio was0.10，andpositive likelihood ratio was6.11；In31patients with cavity effusion, sensitivity ofT-SPOT.TB was80％(8/10)，specificity was48％(10/21)，negative predictive value was83.3％，positive predictive value was42.1％，negative likelihood ratio was0.42，and positivelikelihood ratio was1.54.Among22patients diagnosed active tuberculosis，the positive rate of T-SPOT.TBassay，acid-fast staining of sputamentum，tuberculosis antibody with ELISA assay andhisopathology diagnosis were86.3%、22.2%、9.1%、57.1%respectively. Sensitivity ofcombination of T-SPOT.TB assay and hisopathology diagnosis was100%.Conclusion：The negative result of T-SPOT.TB is useful to exclude active tuberculosis. Combinationof T-SPOT.TB assay and hisopathology diagnosis is recommended in routine clinicalpractice．...