ABSTRACT
The use of common reagent containers for mass staining of sputum smears for acid fast bacilli (AFB) by the Ziehl-Neelsen (ZN:) Technique has previously been discouraged for fear of cross contamination. We undertook the present study to ascertain whether this fear has any justification. Out of 1296 smears prepared from 198 specimens including 9 known negative controls; 108 stainings were performed. 70 specimens and all positive controls were repeatedly positive on different stainings. 69 (99) cases and all positive controls were confirmed by culture. No carry over of AFB from positive to negative smears was experienced. Time; cost and staining mess was significantly reduced during mass eestaining. The use of a common container for staining of sputum smears for AFB by the ZN technique is not only economical but also ideal for laboratories where space is insufficient and larg numbers of sputum specimens are involved