This study was performed to assess the impact of sputum acid-fast bacilli (AFB) smear in predicting pulmonary tuberculosis (TB). We retrospectively identified sputum AFB smear specimens over a 6-year period in our hospital. A total of 1814 specimens were included: 26 were culture-positive for TB, and 116 were for nontuberculous mycobacterium (NTM). NTM were more frequently isolated than TB (odds ratio: 4.7, 95% confidence interval (95% CI); P <0.001). Sensitivity, specificity, and positive likelihood ratio of sputum AFB smear for TB were 42.3% (95% CI 23.4-63.1), 94.5% (95% CI 93.3-95.5), and 7.64 (95% CI 4.69-12.45), respectively. Although there was a statistical significance in the positive likelihood ratio, sputum smear test had a positive predictive value of 0.100 (95% CI 0.051-0.172). These data suggest that the diagnostic yield of sputum AFB smear for pulmonary TB might be substantially low in our clinical setting. Physicians should pay attention to interpretation of sputum smear results especially in areas with high prevalence of NTM.

We have performed optional screening tests for the detection of pancreatic and biliary duct lesions since 2010 at Itoigawa General Hospital in Niigata, Japan. Here, we report the test results over a 10-year period. In total, 79 participants (51 male, 65%; mean age, 64 years) were screened. Fifteen participants were positive for antinuclear antibodies. Elevated serum IgG4 was found in 1 participant. None had positive antimitochondrial antibody. On magnetic resonance cholangiopancreatography, there was no evidence of pancreatic and biliary duct autoimmune disorders or cancer, but we suspected branch-duct intraductal papillary mucinous neoplasia in 1 participant. Because of potential selection bias in the characteristics of the participants who choose to undergo screening, an important question is how to identify those who might have malignancy and should undergo more sensitive imaging examinations. Performing antibody tests for biliary autoimmune diseases needs to be reconsidered.