Diagnostic Yield of Sputum Acid-Fast Bacilli Smear for Pulmonary Tuberculosis Decreases with High Prevalence of Nontuberculous Mycobacteria
- VernacularTitle:非結核性抗酸菌の保菌率は喀痰抗酸菌塗抹検査結果の解釈に大きく影響する可能性がある：単施設における後方視的研究
- Author:
Mitsuhiro MATSUO
1
;
Takashi TSUKISHIRO
1
;
Kiyohiro HIGUCHI
1
Author Information
- From:Journal of the Japanese Association of Rural Medicine 2018;67(4):507-
- CountryJapan
- Language:Japanese
- Abstract: 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.
