Abstract:

Objective To investigate the influence factors of false-negative results of QuantiFERON-TB Gold In-Tube (QFT-GIT) in active pulmonary tuberculosis patients. Methods A total of 1287 patients with active pulmonary disease admitted to Hunan Chest Hospital from July to October 2018 were collected as study subjects, they were diagnosed individually or jointly based on medical history, clinical symptoms, signs, imaging, bacteriology, pathology and diagnostic treatment; 1072 patients were finally included according to inclusion and exclusion criteria. Multivariate logistic regression analysis was used to analyze independent risk factors for the false negative results of QFT-GIT in patients with active pulmonary tuberculosis patients. Results All the 1072 patients could be divided into 188 false-negative cases (17.5%) and 884 true positive cases (82.5%). Among the true positive cases, patients aged 40- and 60-92 years old were 32.1% (284/884) and 23.0% (203/884), respectively; 18.3% (162/884) were re-treated patients; 11.0% (97/884) were pulmonary tuberculosis with extra-pulmonary tuberculosis; 72.5% (641/884) were with negative mycobacterial cultures; 9.6% (85/884) with albumin <35 g/L; lymphocyte count <0.6×10 ⁹/L in 1.8% (16/884). Among the false-negative cases, 36.7% (69/188) and 38.8% (73/188) were aged 40- and 60-92 years old, respectively; 31.4% (59/188) were re-treated patients; 20.7% (39/188) were with pulmonary tuberculosis and extra-pulmonary tuberculosis; 86.2% (162/188) were negative in mycobacterial cultures; 19.1% (36/188) with albumin <35 g/L; 7.4% (14/188) with lymphocyte count <0.6×10 ⁹/L. All the differences were statistically significant (χ ² values were 31.819, 16.085, 13.574, 16.651, 14.072, and 18.109, respectively; P<0.05). According to multivariate analysis, patients aged 40- years old (OR=1.972, 95%CI=1.306-2.976,P=0.001), 60-92 years old (OR=2.782, 95%CI=1.832-4.224,P<0.001), re-treated tuberculosis (OR=1.741, 95%CI=1.174-2.581,P=0.006), pulmonary tuberculosis and extra-pulmonary tuberculosis (OR=2.043, 95%CI=1.314-3.176,P=0.002), negative mycobacterial culture (OR=3.354,95%CI=2.066-5.446,P<0.001), albumin <35 g/L (OR=2.777, 95%CI=1.721-4.481,P<0.001), lymphocyte count <0.6×10 ⁹/L (OR=3.662, 95%CI=1.679-7.987,P=0.001) were independent risk factors for false-negative result of QFT-GIT. Conclusion Aged 40- years old, re-treated tuberculosis, pulmonary tuberculosis with extra-pulmonary tuberculosis, culture-negative, albumin <35 g/L, and lymphocyte count <0.6×10 ⁹/L are independent risk factors for false-negative results of QFT-GIT in patients with active pulmonary tuberculosis.

Key words: Tuberculosis,pulmonary, Enzyme-linked immunosorbent assay, False negative reactions, Factor analysis,statistical