Prospective comparison of cytological specimen adequacy assessment by different rapid staining techniques for rapid on-site evaluation in fine needle aspiration cytology and their cost-effectiveness.

Objective: Rapid on-site evaluation (ROSE) is a technique beneficial in determining the adequacy of the samples, thereby increasing the diagnostic yield, useful in triage of specimens for ancillary studies and can also help determine a preliminary diagnosis in emergency cases. The different rapid stains for on-site evaluation described in the literature are diff quik, toluidine blue (TB), brilliant cresyl blue (BCB), ultra-fast Pap stains, and rapid hematoxylin and eosin (H&E). This study was undertaken as there is sparse literature regarding the best and the most cost-effective rapid stain.

Method: Fine needle aspiration samples from 200 patients with palpable swellings in easily accessible regions were taken. Smears stained by rapid and routine stains were assessed based on four parameters, with provisional diagnosis on the rapid stained smears. A comparative analysis of the advantages and disadvantages of the rapid stains was carried out with appropriate statistical tests with the routinely stained smears as gold standard.

Results: There was adequate material in 100% of ROSE smears. rapid pap stained smears showed well preserved cytoplasmic details, nuclear details, and background details. The time taken was least with TB and BCB being 5 s each. The most cost-effective was found to be TB.

Conclusions: We conclude that TB is the most cost-effective, quick, least labor-intensive, and reliable rapid stain for ROSE especially in resource-poor settings.