Email Alert | RSS

Chinese Journal of Antituberculosis ›› 2020, Vol. 42 ›› Issue (12): 1299-1304.doi: 10.3969/j.issn.1000-6621.2020.12.009

• Original Articles • Previous Articles     Next Articles

Analysis on risk factors associated with false negative results of interferon-gamma release assay in active tuberculosis

MA Jin-bao, MA Ting-ting, REN Fei, YANG Han(), TAN Gan-wen   

  1. Department of Drug-resistance tuberculosis, Xi’an Chest Hospital, Xi’an 710100, China
  • Received:2020-04-16 Online:2020-12-10 Published:2020-12-24
  • Contact: YANG Han E-mail:xajhyanghan@163.com

Abstract:

Objective To analysis risk factors associated with false negative result of interferon-gamma release assay (IGRA) in pulmonary tuberculosis with positive sputum smear. Methods A total of 196 pulmonary tuberculosis patients with positive sputum smear were collected from June to December 2019 in Xi’an Chest Hospital, including 145 males (74.0%) and 51 females (26.0%); the median age (M(Q1,Q3)) was 38 (26, 53) years. They were divided into IGRA positive group (n=106) and false negative group (n=90). Data of general information, clinical symptoms, results of laboratory test and chest CT findings were collected. Multivariate logistic regression analysis was used to analyze the risk factors associated with false negative result of IGRA in pulmonary tuberculosis patients with positive sputum smear. Results Among the 196 patients, 106 cases were IGRA positive (54.1%). The white blood cell count (M(Q1,Q3)) of IGRA positive group was 6.3 (5.0, 7.5)×109 cells/L, which was statistically lower than that of IGRA false negative group (7.4 (5.8, 9.2)×109 cells/L) (Z=-3.464, P=0.001); the erythrocyte sedimentation rate (M(Q1,Q3)) in IGRA positive group was also statistically lower than that in IGRA false negative group (34.5 (16.0,58.0) mm/1 h vs. 53.0 (31.8, 84.3) mm/1 h, Z=-3.492, P=0.000); however, the number of CD4+T lymphocytes in IGRA positive group was statistically higher than that in IGRA false negative group (553 (371,737) cells/μl vs. 432(320, 645) cells/μl, Z=-2.080, P=0.038). Using multivariate logistic regression analysis, it was showed that white blood cell count ≥7.0×109 cells/L (OR(95%CI)=3.003 (1.618-5.572)), erythrocyte sedimentation rate ≥40mm/1 h (OR(95%CI)=2.270 (1.228-4.195)), CD4+T cell <400 cells/μl (OR(95%CI)=2.198(1.155-4.181)) were dependent risk factors for false negative result of IGRA in pulmonary tuberculosis with positive sputum smear. Conclusion The increase of white blood cell and erythrocyte sedimentation rate, as well as the decrease of CD4 +T cell are dependent factors for false negative result of IGRA, the clinical application of IGRA to aid tuberculosis diagnosis should combine with other factors of patients.

Key words: Tuberculosis,pulmonary, Interferon-gamma, Immunologic tests, Risk factors, Factor analysis,statistical