Abstract: Objective To evaluate the value of interferon-gamma release assay (T-SPOT.TB) in the diagnosis of tuberculosis lymphadenitis. Methods From July 2011 to Dec 2013, 185 patients with enlarged lymph node were enrolled and categorized as histopathology-confirmed tuberculosis lymphadenitis group (n=51) and no-tuberculosis lymphadenitis group (n=105). The remaining inconclusive patients were excluded from final analysis. T-SPOT.TB with peripheral blood and tuberculosis antibody with serum by using western blot method were detected in all patients. Statistical analysis was performed using SPSS 17.0. The measurement data of non normal distribution were expressed with the median. Spot forming cells(SFCs) were compared in different groups using nonparametric Mann Whitney U test. Comparisons between proportions were performed using Chi-squared test. Results The sensitivity and specificity of T-SPOT.TB assay were 92.2％(47/51) and 79.0％(83/105) respectively, however, they were 60.8％(31/51) and 77.1％(81/105) in tuberculosis antibody, respectively. The sensitivity of T-SPOT.TB assay was significantly higher than that of tuberculosis antibody with statistically significant (χ² =13.95，P<0.01). Also, SFCs median of tuberculosis lymphadenitis group and non-tuberculosis lymphadenitis group were 242(57, 621)/ 10⁶ PBMCs and 0(0, 20) /10⁶ PBMCs, respectively. SFCs was significantly higher in the tuberculosis lymphadenitis group than that in non-tuberculosis lymphadenitis group (U=472.0，P<0.01). In the 69 patients with positive T-SPOT.TB results, SFCs median with 280（98，684）/10⁶ PBMCs in the 47 patients with tuberculosis lymphadenitis was significantly higher than 52(35，93）/10⁶ PBMCs in the 22 patients with non-tuberculosis lymphadenitis (U=146.5，P<0.01). Conclusion The T-SPOT.TB assay is high sensitivity in the diagnosis of tuberculosis lymphadenitis. It could be a useful adjunctive tool for diagnosis of tuberculosis lymphadenitis.

Key words: Tuberculosis, lymph node/diagnosis, Interferon-gamma release tests, Sensitivity and specificity