Clinical application of acid-fast bacilli smear method based on liquid-based cytology

HE Xiong; YANG Li-kun; CAO Yan-long; SUN Wen-na; WANG Xin-jing; CHENG Xiao-xing; WANG Zhong-yuan

doi:10.3969/j.issn.1007-8134.2016.03.007

Abstract：ObjectiveTo evaluate the diagnostic performance of smear method based on liquid-based cytology in detecting acid-fast bacilli in clinical specimens of different types.MethodsA total of 200 samples including 148 samples of morning sputum and 52 samples of body fluid, which were collected from patients within one week since they were hospitalized, were examined for acid-fast bacilli by direct smear method and liquid-based smear method at the same time. The positive rates of the two methods were compared.ResultsSixteen repeated samples and 9 samples without being cultured for acid-fast bacilli were excluded, so 123 samples of morning sputum and 52 samples of body fluid were included. As for 123 sputum samples, the positive rates were 33.33% for liquid-based smear method and 24.39% for direct smear method, and the difference was significant (P=0.012); the positive rates were 58.82% for liquid-based smear method and 44.12% for direct smear method in culture-confirmed sputum samples, and the difference was significant (P=0.018). As for 52 samples of body fluid, the positive rates were 13.46% for liquid-based smear method and 1.96% for direct smear method, and the difference was significant (P=0.041); 7 samples were positive for liquid-based smear method and 1 for direct smear method in culture-confirmed sputum samples (16 samples), and the difference was significant (P=0.040).ConclusionsThe positive rate of detecting acid-fast bacilli by liquid-based smear method is higher than that by direct smear method, especially for body fluid specimens. The liquid-based smear method is useful for clinical rapid diagnosis. However, for the sputum specimens, the examination time and the cost should be considered.