Diagnostic efficacy of 4 detection methods in diagnosis of pulmonary tuberculosis

OBJECTIVE  To evaluate the value of smear acid-fast staining, mycobacterium culture, T-cell spot test for tuberculosis infection (T-SPOT.TB) and Mycobacterium tuberculosis/rifampicin resistance real-time fluorescent quantitative nucleic acid amplification detection technology (GeneXpert MTB/RIF), as well as their combined detection, in the diagnosis of pulmonary tuberculosis.

METHODS  The detection results of suspected pulmonary tuberculosis patients who simultaneously underwent acid-fast smear, mycobacterium culture, T-SPOT.TB and GeneXpert MTB/RIF tests at Zhongshan Hospital, Fudan University from May 2021 to Jun. 2023 were collected. A total of 392 clinically confirmed pulmonary tuberculosis patients and 1 851 non-tuberculosis patients were included. With clinical diagnosis as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the aforementioned 4 methods and their combined detection were calculated, and the receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic efficacy of the 4 methods alone or in combination in the diagnosis of pulmonary tuberculosis.

RESULTS  The sensitivities of acid-fast smear, mycobacterium culture, T-SPOT.TB and GeneXpert MTB/RIF detection were 13.01%, 53.83%, 91.84% and 57.65%, respectively. The specificities were 98.11%, 100.00%, 73.20% and 99.84%, respectively. The areas under the ROC curve (AUC) were 0.556, 0.769, 0.825 and 0.787, respectively. The detection sensitivity and AUC of T-SPOT.TB were higher than those of the other three methods (P＜0.05). The combined use of T-SPOT.TB and GeneXpert MTB/RIF yielded the highest AUC (0.847) (P＜0.001).

CONCLUSIONS  T-SPOT.TB exhibits high sensitivity and can be used for initial screening of pulmonary tuberculosis. GeneXpert MTB/RIF demonstrates high specificity and can serve as the preferred etiological diagnostic method for pulmonary tuberculosis. The combined detection of T-SPOT.TB and GeneXpert MTB/RIF contributes to improving the diagnostic efficacy of pulmonary tuberculosis.