Background: Sputum smear microscopy is rapid, economic, and useful to detect patients with transmittable tuberculosis, albeit laborious. We aimed to evaluate the usefulness of an automated acid-fast bacilli stainer, which had been developed for lowering the labor and maintaining or increasing the staining quality.

Methods: One hundred sputum samples including some known positive smear specimens which were selected from clinical specimens requested for smear and culture for mycobacteria at Pusan National University Hospital, were used for evaluation. Auramine/rhodamine fluorescent acid-fast stainings were performed manually or by using the automated stainer, AT-2000F (Dagatron, Ilsan, Korea). Ziehl-Neelsen stain was also performed simultaneously.

Results: Concordance rate between automated and manual fluorescent stains was 98.0% and that between automated fluorescent and manual Ziehl-Neelsen stains was 88.0%. In all discordant cases, the automated stains showed one-grade higher results compared to the respective manual fluorescent or Ziehl-Neelsen stains. With the automatic stainer, all staining procedures were processed automatically except for slide loading and unloading. The process time was reduced by a half, and the slide-to-slide or day-to-day variations of staining quality were reduced compared with the manual fluorescent stain.

Conclusion: Acid-fast bacilli stain using automated stainer AF-2000F can reduce the processing time, labor, and variations of staining quality, and enhance or maintain the detection of positive smears. (Korean J Clin Microbiol 2006;9(1):115-118)