Comparison of tuberculin skin test and Quantiferon-TB Gold In-Tube assay in young male patients with pulmonary tuberculosis

Abstract

Objective: To compare Quanti FERON-TB Gold In-Tube Test (QFT-G) and tuberculin skin test (TST) in terms of diagnostic efficiency in young male patients with pulmonary tuberculosis. Material and Methods: A total of 58 soldiers who were followed up with the diagnosis of smear and culture positive pulmonary tuberculosis between March 2007 and March 2008 were enrolled in the study in a military hospital which is a center of tuberculosis in Istanbul. Thirty-nine soldiers who were considered to be healthy were taken as the control group. TST and QFT-G were applied to study group and the control group. For TST, endurations ≥15 mm were accepted as positive in the subjects with BCG vaccination and ≥10 mm were accepted as positive in the ones without BCG. For QFT-G, samples ≥0.35 IU/ml were accepted as positive. Sensitivity, specifity, positive and negative predictive values of two tests were calculated. Results: QFT-G was found positive in 53 (91.4%) and TST was found positive in 29 (50%) of 58 patients with pulmonary tuberculosis. While the result was detected as indefinite in one patient in control group, QFT-G was found negative in 36 (94.7%) and TST was found negative in 29 (76.3%) subjects. Sensitivities of QFT-G and TST were found as 91.4% and 50%, specifities were found as 94.7% and 76.3%, positive predictive values were found as 96.4% and 76.3%, negative predictive values were found as 87.8% and 50%, respectively. Conclusion: QFT_G was detected to have higher specifity, sensitivity, positive and negative predictive values compared to TST. We conclude that QFT-G can be used more effectively in the diagnosis of tuberculosis infection when compared to TST. © 2011 by Türkiye Klinikleri.