Application of Acid-fast staining combined with MTB/RIF GeneXpert in the diagnosis of Nontuberculous Mycobacteria Pulmonary Disease.

Abstract Objective To evaluate the clinical diagnostic value of positive acid-fast staining combined with negative MTB/RIF GeneXpert in the diagnosis of nontuberculous mycobacteria pulmonary disease (NTM-PD). Methods We consecutively included 133 inpatients with confirmed NTM-PD between January 1, 2018 and December 31, 2019, at Tongji Hospital and Jinyintan Hospital, Tongji Medical College of Huazhong University of Science and Technology, in Wuhan, China. One hundred patients with confirmed pulmonary tuberculosis (PTB) were randomly included as the control group. Results The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of positive acid-fast staining combined with a negative MTB/RIF GeneXpert result were 51.13% (95% confidence interval (CI), 42.52-59.73), 97.00% (95% CI, 93.60-100.40), 95.78% (95% CI, 90.98-100.57) and 59.88% (95% CI, 52.25-67.51), respectively. When subjects were limited to patients with positive acid-fast staining, the sensitivity of a negative MTB/RIF GeneXpert result was 88.31% (95% CI, 80.97-95.65). When acid-fast staining was conducted ≥3 times, the sensitivity of this combination diagnosis method increased to 61.67% (95% CI, 49.00-74.33). Conclusions Positive acid-fast staining combined with a negative MTB/RIF GeneXpert result could be an effective and time-saving method for the diagnosis of NTM-PD.