Abstract:

Objective To investigate the diagnostic value of serum tuberculosis(TB) antibody, which relative molecular mass is 38000 (38kD-IgG) for active tuberculosis and compare it with T-SPOT.TB.Methods Two thousand one hundred and forty-six patients with active TB and 1671 patients with non-TB pulmonary disease were retrospectively included, analyzed and compared diagnostic value of serum TB antibodies for bacteriological confirmed TB, clinically diagnosed TB and extrapulmonary TB by receiver operating characteristic curve (ROC), compared sensitivity, specificity, and area under the curve (AUC) of T-SPOT.TB and serum TB antibody, finally evaluated auxiliary diagnostic value of serum TB antibody for active TB.Results Our data showed that sensitivity of serum TB antibody for patients with bacteriological confirmed TB (47.1%,246/522) was higher than that for patients with clinically diagnosed (25.9%,388/1499) and extrapulmonary TB (24.8%,31/125) χ ²=81.15 and 20.53, respectively; Ps<0.001. The sensitivity of patients with clinically diagnosed patients and extrapulmonary TB had no statistical difference,χ ²=0.07, P=0.790. The sensitivity (30.6%,657/2146) of serum TB antibody for active TB was lower than that of T-SPOT.TB (76.2%,1635/2146),χ ²=799.00,P=0.000, its AUC (0.619,95%CI:0.604-0.635) was lower than that of T-SPOT.TB (0.781,95%CI:0.768-0.794), χ ²=14.00,P=0.000. However, the specificity of serum TB antibody (93.2%,1557/1671) was higher than that of T-SPOT.TB (70.1%,1171/1671),χ ²=316.00,P=0.000. Conclusion The sensitivity of serum TB antibody applied in clinics needs to get improved, much more sensitive TB antibody diagnostic kit should be developed in order to provide better diagnostic tools for clinics.

Key words: Tuberculosis, Immunoglobulin G, Reagent kits, diagnostic, Comparative study, Data interpretation, statistical