Evaluation of Optimized Toluidine Blue Stain as an Alternative Stain for Rapid On-Site Evaluation (ROSE).

: Rapid on-site evaluation (ROSE) is crucial for improving the diagnostic yield of fine-needle aspiration (FNA) biopsies. Despite recent advances in ROSE, such as telecytology, the rapid stains used in this process have not seen significant innovation. Diff-Quik (DQ) and Toluidine Blue (TB), the most common ROSE stains, have significant limitations. This study evaluates the optimized Toluidine Blue stain, a mixture of oluidine Blue, osin, and lcohol (TEA), as a potential alternative to TB or DQ for ROSE. : A comparative study was conducted using fifty remnant body fluid specimens with adequate cellularity, collected at the University of California Davis Medical Center over six months. Two smears were prepared from each specimen. One was stained with TB, and the other with optimized Toluidine Blue (TEA). Digital images of each slide were evaluated by three cytologists and two cytopathologists, blinded to the stain, using five criteria: background staining, cytoplasmic detail, nuclear membrane clarity, chromatin texture, and nucleoli staining. Each criterion was scored on a scale of 1 to 3. : Optimized Toluidine Blue (TEA) stain demonstrated superior overall image quality compared to TB. Specifically, optimized Toluidine Blue (TEA) showed significantly less background staining ( < 0.05) and improved nuclear membrane clarity ( < 0.05), chromatin texture ( < 0.05), and nucleoli detail ( < 0.05). There was no significant difference between the two stains in the assessment of cellularity or cytoplasmic detail. : The optimized Toluidine Blue (TEA) stain shows promise as a rapid stain for ROSE, offering rapid processing and improved digital image quality. Further evaluation of optimized Toluidine Blue (TEA) stain on FNA specimens is warranted to validate these findings and explore its potential to enhance telecytology in ROSE.