To analyze the consistency between the Mycobacterium tuberculosis loop-mediated isothermal amplification (Mycobacterium tuberculosis loop-mediated isothermal amplification, TB-LAMP) and the tuberculosis T-cell spot test (tuberculous infection of T cells spot test, T-SPOT.TB) in the diagnosis of tuberculosis (tuberculosis, TB), as well as the influencing factors of the accuracy of combined diagnosis.

A total of 556 suspected TB patients hospitalized in our hospital from January 2022 to December 2024 were selected. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic values of the two methods used alone and in combination. The Kappa test was employed to assess the consistency between the two methods and Mycobacterium tuberculosis (MTB). Univariate and multivariate Logistic regression analyses were conducted to identify the factors influencing the combined diagnostic accuracy of the two methods.

The positive rates of TB-LAMP in the three groups were 87.32%, 75.00%, and 12.23% respectively, those of T-SPOT.TB were 92.39%, 71.74%, and 23.40% respectively, and those of the combined detection were 93.48%, 85.87%, and 18.09% respectively, with significant differences among the groups (P<0.001). There was a high consistency between T-SPOT.TB, TB-LAMP, and their combined detection and MTB culture (Kappa=0.747, 0.733, 0.751). The sensitivities of TB-LAMP, T-SPOT.TB, and the combined detection were 84.24%, 87.23%, and 91.58% respectively, the specificities were 92.63%, 90.43%, and 83.51% respectively, the diagnostic accuracies were 87.41%, 88.31%, and 88.85% respectively, and the AUCs were 0.840, 0.910, and 0.930 respectively. Age≥60 years, CD4⁺ T lymphocyte count<350 cells/μL, albumin<35 g/L, diabetes, number of specimen submissions<3 times, time from collection to processing>2 h, and failed microscopic examination were independent risk factors affecting the combined diagnostic accuracy (P<0.05). Genderstratified analysis showed that except for age which was not significant in the female subgroup, all other risk factors remained independently significant in both male and female subgroups. Gender did not substantially interfere with the effects of these risk factors.

The combined detection of TB-LAMP and T-SPOT.TB can significantly improve the diagnostic accuracy. Age≥60 years old, CD4⁺ T lymphocyte count<350 cells/μL, albumin<35 g/L, diabetes, number of tests sent for examination<3 times, collection-to-processing time>2 hours, and insufficiently qualified for microscopic examination are all independent risk factors affecting the accuracy of the combined diagnosis.