Abstract:

Objective: To evaluate the efficacy of QuantiFERON-TB Gold Plus (QFT-Plus) for the detection of active tuberculosis. Methods: A total of 1360 patients who were hospitalized and underwent QFT-Plus test in Guiyang Public Health Clinical Centre from January 2023 to January 2024 were retrospectively collected. After excluding 36 uncertain patients, 985 patients were in the tuberculosis group and 339 patients were in the non-tuberculosis group. The basic information, clinical manifestations, laboratory test results and imaging examination data of the patients were collected. Sputum smear antacid bacilli, sputum culture, GeneXpert MTB/RIF test for carrier bacilli were graded in the TB group and analyzed in relation to the QFT-Plus test results; sputum smear antacid bacilli and sputum culture results were divided into a positive group and a negative group, and classified into 3 grades of mild, moderate, and severe tuberculosis according to the grading criteria of the degree of severity, and the IFN-γ in the tube of the antigens of TB1, TB2, TB2-TB1 was analysed in comparison. Results: Out of 1324 patients, 985 were in the tuberculosis group and 339 were in the non-tuberculosis group, the sensitivity of QFT-Plus for detecting active tuberculosis was 94.11% (927/985), specificity was 51.62% (175/339), positive predictive value was 84.97% (927/1091) and negative predictive value was 75.11% (175/233), the coincidence rate was 83.23% (1102/1324). The IFN-γ levels in TB1 tube, TB2 tube and TB2-TB1 in the tuberculosis group were 5.11 (2.00, 9.90) IU/ml, 6.24 (2.54, 10.00) IU/ml, and (0.66±1.58) IU/ml, which were higher than those in the non-tuberculosis group (0.38 (0.07, 3.37) IU/ml, 0.41 (0.08 4.12) IU/ml, (0.27±1.16) IU/ml), and the differences were statistically significant (Z=-14.970,P<0.001;Z=15.230,P<0.001;t=-4.910,P<0.001). The IFN-γ levels of TB2 and TB2-TB1 in the sputum smear antacids-positive group were 6.81 (3.27, 10.00) IU/ml and (0.85±1.80) IU/ml, which were higher than those in the negative group (5.61 (2.21, 10.00) IU/ml and (0.53±1.41) IU/ml), and the difference was statistically significant (Z=-3.060, P<0.001; t=-2.920, P<0.001). The IFN-γ levels of TB1 and TB2 in the positive group of sputum culture were 5.37 (2.46, 10.00) IU/ml and 7.08 (3.86, 10.00) IU/ml, which were higher than those of the negative group (4.44 (1.56, 9.41) IU/ml and 5.04 (1.90, 10.00) IU/ml), and the difference was statistically significant (Z=-3.450, -4.920, P<0.001). Comparison of IFN-γ levels in tuberculosis antigen tubes of different severity showed 5.12 (2.57,10.00) IU/ml, 6.04 (3.20,10.00) IU/ml, (0.49±1.16) IU/ml in TB1, TB2, TB2-TB1 and 5.33 (2.06,10.00) IU/ml, 6.45 (2.54,10.00) IU/ml, (0.62±1.46) IU/ml in the severe tuberculosis group and 4.27 (1.82,9.43) IU/ml, 5.97 (2.37,10.00) IU/ml, (0.79±1.85) IU/ml in the moderate tuberculosis group, the difference was not statistically significant (Z=4.040,P=0.133; Z=0.910, P=0.634; t=2.400, P=0.091). Conclusion: QFT-Plus test has good clinical value in the auxiliary diagnosis of active tuberculosis.

Key words: Tuberculosis, pulmonary, Interferon regulatory factors, Diagnosis