Abstract：Objective To explore the accuracy and application range of T cell antigen seimulation test (T-SPOT) in the screening of tuberculosis (TB) cases in the general population, high-risk group and suspected tuberculosis group through analyzing the specificity and sensitivity of T-SPOT.TB assay in the clinical detection of TB infection. Methods Patients with confirmed tuberculosis and those without in the People’s Hospital of Xiangxi Autonomous Prefecture from May to September, 2016 were selected as the research objects. Peripheral blood was collected to separate peripheral blood mononuclear cells (PBMCs). T-SPOT.TB assay, acid-fast bacilli stain, purified protein derivatives of tuberculin (PPD) skin test and serum tuberculosis antibody (TB-Ab) were employed for detecting TB infection in the two groups, and the sensitivities and specificities of the 4 Methods were statistically analyzed. The positive rates of TB infection screened by T-SPOT.TB assay among different populations were predicted. Results The sensitivity and specificity of T-SPOT.TB assay for TB screening were 93.4% and 77.3% respectively. The positive rate of T-SPOT.TB assay was significantly higher in the tuberculosis group than in the non-tuberculosis group (93.3% vs. 22.6%, χ2=152.81, P<0.01). Comparison of different tuberculosis infections within the tuberculosis group as well as within the non-tuberculosis group showed that T-SPOT.TB assay used as an auxiliary tool was helpful in the diagnosis of TB. The Kappa values of T-SPOT.TB assay, acid-fast bacilli stain, PPD skin test and serum TB-Ab were 0.691, 0.183, 0.525 and 0.185 respectively. Only the Kappa value of T-SPOT.TB assay was higher than 0.6, indicating its higher consistence with real situation and igher accuracy. The predictive positive rates by T-SPOT.TB assay in the general population, high-risk group and suspected tuberculosis group were 23.03%, 31.07% and 67.75% respectively, but the real TB infection rates were 1.87%, 34.85% and 43.60% respectively.Conclusions The accuracy of T-SPOT.TB assay in the diagnosis of tuberculosis is superior to that of acid-fast bacilli stain, PPD skin test and serum TB-Ab. T-SPOT.TB assay is not suitable for TB screening in the general population, but suitable for TB screening in high-risk group and the auxiliary diagnosis of suspected tuberculosis.
2017, Vol. 24 
