Résumé
To find out the quality of sputum specimens submitted for AFB microscopy, to categorize these specimens on the basis of their quality and to compare the frequency of AFB positive smears in each category of these specimens. Five hundred and seventy convenient sputum samples from patients referred for AFB microscopy of sputum were examine after Ziehi Neelsen staining. Based on Heinman and Radano's criteria for sputum, all the sputa under study were divided into sputum and non-sputum categories. The non-sputum category was sub-divided into saliva and mixed samples based on the ratio of pus cells and epithelial cells. All the smears for qualitative categorization and for AFB were examined by the qualified microbiologist. The frequency of AFB positive smears in each category was calculated. Out of 570 specimens submitted, only 110 [19%] were found to be sputum specimens, while 324 [57%] were saliva and 136 [24%] were declared as mixed. The frequency of AFB positive smears was the highest in samples categorized as sputum, 23.6% [26 out of 110] followed by mixed samples 7.35% [10 out of 136], and saliva 0.31% [1 out of 324]. The overall frequency of AFB positive smears was 6.49% [37 out of 570]. Quality of sputum specimen plays a major role in the detection of AFB from the sputum smears. As evident from this study, the frequency of AFB positive smears in the sputum was found to be much higher as compared to saliva and mixed samples