The Diagnostic Value Of T-SPOT.TB For Tuberculosis And Its Relationship With Age

ObjectiveTo evaluate the clinical significance of tuberculosis specific antigens ESAT-6,CFP-10 and T-SPOT.TB in the diagnosis of tuberculosis and its relationship with age.Explore the cutoff value of T-SPOT.TB in identifying active tuberculosis and inactive tuberculosis.MethodsRetrospective analysis was conducted on 2088 hospitalized adults(?18 years old)who were suspected or exclusion of TB in the First Affiliated Hospital of Anhui Medical University from June 2015 to July 2017,according to the final diagnosis of discharge,they were divided into three groups:active tuberculosis group,inactive tuberculosis and non-tuberculosis group.Then active tuberculosis group was divided into Pulmonary tuberculosis and extra pulmonary tuberculosis group.T-SPOT.TB data were retained in all patients.1)Respectively compared the positive rates of T-SPOT.TB in active tuberculosis group,inactive tuberculosis group and non-TB group,and analysis the date by chi-square test.2)Respectively calculate the Sen?Spe?PV+?PV-of ESAT-6,CFP-10 and T-SPOT.TB in the diagnosis of active tuberculosis,and analysis the date by chi-square test.3)The ROC curves of the active tuberculosis group(PTB,EPTB)and the inactive tuberculosis group were drawn by EAST-6,CFP-10 and T-SPOT.TB respectively,and compared the area under the curve(AUC).4)Search for the cutoff value of T-SPOT.TB to distinguish active tuberculosis from inactive tuberculosis.5)According to age,explore the diagnostic value of T-SPOT.TB in different age groups.Results(1)In the positive rate of T-SPOT.TB diagnosis,the active tuberculosis group(86%)was higher than the inactive tuberculosis(57%),which was significantly higher than the non-tuberculosis group(22.9%)(?2=533.439,P<0.01).As for positive rate,the PTB group was higher than EPTB group(?2=5.2,P<0.05),and the difference was statistically significant.(2)The Sen?Spe?PV+?PV-of the three indicators for the diagnosis of active tuberculosis were as follows:ESAT-6 was 81.56%,79.8%,46.57%,and 95.25%,respectively.CFP-10 was 70.67%,84.5%,49.61%,and 93.03%,respectively.T-SPOT.TB was 86.03%,77.14%,44.83%,and 96.24%,respectively.In the diagnosis of tuberculosis and extra pulmonary tuberculosis,the sensitivity of the T-SPOT.TB test was 90.48%and 82%,respectively.The specificity was 77.14%.(3)The area under the ROC curve of the number of T cell spots of ESAT-6,CFP-10,and T-SPOT.TB was as follows:in the active tuberculosis group,0.874,0.833,and0.891,respectively.In the inactive tuberculosis group,they were 0.595,0.559,and0.605,respectively.The Pulmonary tuberculosis group was 0.905,0.856,and 0.922,respectively.The extra pulmonary tuberculosis group was 0.846,0.813,and 0.865,respectively.(4)When the number of spots of antigen A plus antigen B is 40.5 SFC/2.5X10 5PBMC,it can be used to identify active tuberculosis and inactive tuberculosis infection.(5)In the elderly group and the young and middle-aged group,the sensitivity and specificity of the former T-SPOT.TB detection were lower than the latter.The Sen and Spe of T-SPOT.TB were negatively correlated with age(r=-0.439,-0.241,P<0.05).The T-SPOT.TB sensitivity of the elderly group and the youth group were 76.51%and84.1%,respectively,and as for specificity,were 67.5%and 82.13%,.Conclusions(1)The sensitivity of ESAT-6 antigen is better than that of CFP-10 antigen,and the specificity is lower than that of CFP-10.ESAT-6 and CFP-10 have their own advantages and complement with each other.T-SPOT.TB,the ESAT-6/CFP-10 mixed antigen polypeptide,can greatly improve the sensitivity of detection and is more meaningful for diagnosing tuberculosis.(2)T-SPOT.TB has better diagnostic value in pulmonary tuberculosis than extra pulmonary tuberculosis.(3)When the number of spots of antigen a plus antigen B is 40.5 SFC/2.5X10 ~5PBMC,it can be used to identify active tuberculosis and inactive tuberculosis infection.(4)For T-SPOT.TB,The sensitivity and specificity of TB detection were lower in the elderly group than in the youth group.The Sen and Spe had negative correlations with age(r=-0.439,-0.241,P<0.05).