Objective The aim of this study was to evaluate the diagnostic performance of T-SPOT.TB for tuberculous lymphadenitis.Methods Suspected tuberculous lymphadenitis patients between September 2010 and September 2018 who had both peripheral blood T-SPOT.TB test and lymph node biopsy were retrospectively enrolled in this study.The cutoff value of T-SPOT.TB test for peripheral blood was set as 24 spot forming cell(SFC)/106 periphreral blood monocyte cell(PBMC)according to the instruction of testing kits.The gold standard for diagnosis of TBL was the combination of microbiology results,histopathology results and patient's response to anti-TB treatment.Diagnostic efficacy of T-SPOT.TB was evaluated,including sensitivity,specificity,accuracy,predictive values,and likelihood ratio.Results Among 91 patients who met the inclusion criteria,we excluded 8 cases with incomplete clinical information and 6 cases who lost to follow-up.According to the gold standard,there were 37 cases of true TBL(9 confirmed TBL and 28 probable TBL),30 cases of non-TBL,and 10 cases of clinically indeterminate diagnosis who were excluded from the final analyses.The T-SPOT.TB tests yielded 43 cases of positive response and 24 cases of negative response.The sensitivity,specificity,accuracy,positive predictive value(PPV),negative predictive value(NPV),positive likelihood ratio(PLR)and negative likelihood ratio(NLR)of peripheral blood T-SPOT.TB for diagnosing TBL were 89.2%,66.7%,79.1%,76.7%,83.3%,2.68 and 0.16,respectively.The number of SFCs of T-SPOT.TB in TBL patients[432(134-1264)/106 PBMCs]was higher than that in non-TBL patients[0(0-30)/106 PBMCs]with a significant difference(Z=-5.306,P<0.001).Conclusion T-SPOT.TB is a rapid and simple diagnostic test for TBL with a high sensitivity and negative predictive value.
