Association between extent of intrapulmonary spread on chest CT and false-negative results of T-SPOT.TB in pulmonary tuberculosis: a retrospective study

Background The T-SPOT. TB assay is widely used in adjunctive diagnosis of tuberculosis (TB). However, clinicians often encounter false-negative T-SPOT. TB results. The extent of spread in TB may influence host immune function, which can influence results of the T-SPOT. TB . However, few previous reports have investigated the association between radiologic pulmonary tuberculosis (PTB) severity and T-SPOT. TB results. Methods We retrospectively investigated patients with culture-confirmed pulmonary TB (PTB) at the Jikei University Daisan Hospital between September 2016 and December 2021. We aimed to clarify the association of PTB severity, according to computed tomography (CT), with false-negative results of the T-SPOT. TB test. Results Among 187 patients with PTB, 44 (23.5%) had false-negative T-SPOT. TB results. High rates of false-negative results were considered to be 7/16 (43.7%) with PTB spread in two lung segments (mild PTB) and 16/37 (43.2%) with PTB spread in 19 lung segments (severe PTB). Multivariate logistic regression analysis showed that lymphopenia (odds ratio [OR]: 3.29; 95% confidence interval [CI]: 1.05–10.27; P = 0.04), mild PTB (OR: 4.90; 95% CI: 1.60–14.95; P = 0.005), and severe (OR: 2.89; 95% CI: 1.15–7.26; P = 0.02) were statistically significant risk factors for false-negative results. Conclusion Both mild and severe extent of intrapulmonary lesions on chest CT may be associated with false-negative results of the T-SPOT. TB assay. To estimate intrapulmonary spreads of PTB in chest CT helps diagnosis for PTB with false-negative results of T-SPOT. TB .