Diagnostic Value Of Xpert MTB/RIF、T-SPOT.TB And TB-AB For Smear-negative Pulmonary Tuberculosis

Objective: To explore the value of Xpert MTB/RIF,T-SPOT.TB and tuberculosis antibody in the diagnosis of smear-negative pulmonary tuberculosis.To explore the accuracy of the evaluation of rifampicin resistance with Xpert MTB/RIF.Methods: The patients with suspected pulmonary tuberculosis admitted to the Department of tuberculosis in Tianjin Haihe Hospital from January 2015 to December 2015 were selected immediately.All of the patients examined sputum or bronchoalveolar lavage fluid Xpert MTB/RIF、TB-AB、T-SPOT.TB、3 times of sputum smear and rapid culture of sputum tuberculosis.All patients were treated with Xpert MTB/RIF technique to detect the specific rpo B gene fragment of Mycobacterium tuberculosis by sputum or alveolar lavage fluid.After the diagnosis was made,all of the patients were divided into the initial treatment pulmonary tuberculosis group(144 cases)and other lung diseases group without tuberculosis(control group)(43cases)by clinical diagnosis.According to the results of sputum acid fast staining the pulmonary tuberculosis group divided into smear negative pulmonary tuberculosis group(102 people)and smear positive pulmonary tuberculosis(42 people).By comparing the positive rate/sensitivity of the three detection methods of Xpert MTB/RIF,T-SPOT.TB and serum tuberculosis antibody among different sub groups and in the same group,comparing the pecificity of the three detection methods,and comparing the sensitivity and pecificity between independent and combined detection of the three detection methods,aims to explore the three detection methods in the diagnosis of smear negative pulmonary tuberculosis in their respective characteristics and value,so as to find out the best scheme for the diagnosis of smear negative pulmonary tuberculosis.By comparing the detection of Xpert MTB/RIF drug resistant Mycobacterium tuberculosis with MGIT 960 resistance to rifampicin of Mycobacterium tuberculosis,to investigate the accuracy on the drug resistance of Xpert MTB/RIF and the situation of rifampin resistant Mycobacterium tuberculosis.Results: The Jordon index in the dagnosis of pulmonary tuberculosis by Xpert MRB/RIF、T-SPOT.TB and TB-AB are respectively 56.65%、62.65% and 25.87%.Among the three methods,the Jordon index of T-SPOT.TB is highest.In smear negative pulmonary tuberculosis group and non tuberculosis group,the positive rate of Xpert MTB/RIF was respectively 43.14% and 23.30%,the positive rate of T-SPOT.TB was respectively 77.45% and 18.60%,the positive rate of TB-AB was respectively 30.39% and 11.63%.The positive rate of three detection methods in smear-negative tuberculosis group compared with the control group,by statistical analysis,P<0.05,the difference between the two groups was statistically significant.Compared the sensitivity of the three detection methods in smear negative pulmonary tuberculosis group,the result is T-SPOT.TB>Xpert MTB/RIF>TB-AB,the difference was statistically significant.The specificity of Xpert MTB/RIF、T-SPOT.TB and TB-AB in control group was respectively 97.67%、81.40% and 88.37%.The specificity between Xpert MTB/RIF and TB-AB,by statistical analysis,P>0.05,there was no statistically significant difference between the two methods.The specificity between Xpert MTB/RIF and T-SPOT.TB,by statistical analysis,P<0.05,the difference between the two methods was statistically significant.The specificity between TB-AB and T-SPOT.TB,by statistical analysis,P>0.05,there was no statistically significant difference between the two methods.The Jorden index of T-SPOT.TB was highest by single item detection for diagnosis of smear negative pulmonary tuberculosis,and that is 58.85%.The Jorden index of T-SPOT.TB+Xpert MTB/RIF is 61.79%,and it was the highest among the combined detection of the three detection methods for diagnosis of smear negative pulmonary tuberculosis.But the sensitivity and specificity were not significantly different from those of T-SPOT.TB and T-SPOT.TB+Xpert MTB/RIF+TBAB.The positive rate for diagonosis of smear negative pulmonary tuberculosis of the 2-links with T-SPOT.TB test were significantly higher than that without T-SPOT.TB test,the difference was statistically significant.As MGIT 960 for the gold standard for drug susceptibility of Mycobacterium tuberculosis,the sensitivity and specificity of rifampin resistance by Xpert MTB/RIF was respectively 80% and 100%,the resistant rate of rifampicin was 7.14%.Conclusion: The Jorden index of T-SPOT.TB+Xpert MTB/RIF is the highest among the combined detection of the three detection methods for smear negative pulmonary tuberculosis.T-SPOT.TB can be used for primary screening of smear negative pulmonary tuberculosis.The accuracy of Xpert MTB/RIF for determining rifampicin resistance is high.