Clinical effect of T-SPOT.TB test for the diagnosis of tuberculosis

Background The goal of this study was to further investigate the clinical effectiveness of the T-SPOT.TB test in diagnosing tuberculosis (TB), including the effects of T-SPOT.TB test on evaluating diverse TB types and locations. Methods We collected 20,332 specimens from patients suspected to have TB. Afterwards, we performed an integrative analysis of T-SPOT.TB results and clinical diagnoses, and evaluated the composition ratio and positive detection rate of the T-SPOT.TB test in various age groups, sample types, and hospital departments. In addition, we compared the spot number and composition rate between latent TB infection (LTBI), active TB infection, and old TB infection groups. The active TB group was then further divided into pulmonary TB (PTB), pulmonary and extrapulmonary TB (PETB), and extrapulmonary TB (EPTB) subgroups, and we evaluated whether there were statistical differences in spot number and composition rate between subgroups. Results Positive results from the T-SPOT.TB test were found across different age groups, specimen types, and hospital departments. Elderly patient groups, pleural effusion samples, and thoracic surgery departments showed the highest rates of positivity. There were no statistically significant differences in spot number of CFP-10 and ESAT-6 wells between disease groups or active TB subgroups. The composition rate, however, was significantly different when ESAT-6 and CFP-10 wells were double-positive. The spot number and composition rate were statistically different between the three disease groups, but showed no significant differences between the three subgroups of active TB. Conclusions The results of T-SPOT. TB test showed differences in LTBI, active TB and old TB. Additionally, a higher spot number level was observed in the active TB group.