Concentration of sputum by cytocentrifugation for preparation of smears for detection of acid-fast bacilli does not increase sensitivity of the fluorochrome stain.

To evaluate the usefulness of cytocentrifugation for detection of acid-fast bacilli (AFB) in sputum specimens, we compared this method to a traditional concentration method for the preparation of smears. A total of 844 sputum specimens (from 579 patients) of adequate volume that were submitted for detection of mycobacteria were evaluated. A portion of each specimen was used for cytocentrifugation; the remainder was processed by our decontamination-concentration protocol (2% sodium hydroxide-N-acetyl-L-cysteine; centrifugation at 3,600 x g for 15 min) for preparation of smears and culture.