Application of T-SPOT.TB in the Early Diagnosis of Tuberculosis / 现代检验医学杂志

ABSTRACT

Objective This study aims to explore the application value of tuberculosis T lymphocytes enzyme-linked immune SPOT test (T-SPOT.TB) on early diagnosis of tuberculosis.Methods The TB infection in 189 inpatients suspected tuberculosis in pneumology department of Shaanxi Provincial People's Hospital was detected with T-SPOT.TB,fluorescence RQPCR,tuberculosis (TB-Ab)protein chip and PPD methods.Results The sensitivity of four methods was 91.54％ (119/130),73.85％(96/130),63.08％(82/130) and 57.69％ (75/130) respectively and the specificity of those was 89.83％ (53/59),86.44％(51/59),67.79％(40/59) and 66.10％(39/59),respectively.The sensitivity of T-SPOT.TB method was statistically higher than those of other three tests,respectively (P＜0.05).The specificity of T-SPOT.TB was significantly higher than those of TB-AB and PPD (P＜0.05),but there was no statistical difference between RQ-PCR and T-SPOT.TB (P＞0.05).The positive predictive values of T-SPOT.TB,fluorescent quantitative PCR,TB-Ab and PPD assays were 95.2％ (119/1250),92.3％ (96/104),81.2％ (82/101) and 78.9％ (75/95) respectively while the negative predictive values of those were 82.8％ (53/64),60％ (51/85),45.5％ (40/88) and 41.5％ (39/94),respectively.The false-positive rates (misdiagnosis rate) of four assays were 10.2％ (6/59),13.6％ (8/59),32.2％ (19/59) and 33.9％ (20/59) respectively and the false-negative rates (rates of missed diagnosis) of those were 8.5％ (11/130),26.2％ (34/130),36.9％ (48/130)and 42.3 ％ (55/130),respectively.The negative likelihood ratios of T SPOT.TB,fluorescent quantitative PCR,TB-Ab and PPD assays were 0.11,0.16,0.48 and 0.51 respectively,meanwhile the positive likelihood ratios of T-SPOT.TB,fluorescent quantitative PCR,TB-Ab andPPD assays were 9.0,5.4,2.0 and 1.7,respectively.What' s more,the diagnostic accordance rates of the four assays were 91.0％ (172 189),77.8％ (147 189).64.6％ (122/189) and 60.3％ (114/189),respectively.Conclusion T-SPOT.TB test is a more sensitive and specific method and of great significance to the early diagnosis of TB,which has more clinical value in different stages of tuberculosis diagnosis.