'Ease of interpretation' of cytological smears stained with modified ultrafast papanicolaou stain: Interobserver agreement and reproducibility.

Abstract

Since its inception in 1995, the Ultrafast Papanicoloau (UFPAP) cytological stain has undergone a number of modifications to suit the local availability of reagents and cost in different set ups. However, the reported results have been uniformly encouraging. We designed a study to investigate the inter-observer agreement in 'perceived ease of interpretation' of cytological smears stained with Modified Ultrafast Papanicoloau stain (MUFPAP). After a small pilot study, we prospectively stained air-dried fine needle aspirate smears (FNACs) and Body Fluid smears with the standardized MUFPAP stain. The MUFPAP stained slides were evaluated in tandem with other routine cytological stains as well as independently by two pathologists. Two rater kappa was used to determine the agreement. The study included 93 fluids and 34 FNACs. A vast majority of the cases stained with MUFPAP were rated 'better' than the routine stains in terms of 'overall ease of interpretation' with considerable agreement. The agreement tended to be better for FNACs than fluid specimens. Cases with malignant pathology demonstrated a perfect agreement (kappa = 1) between the raters in terms of 'overall ease of interpretation' (91.7% cases were rated 'very good' by each pathologist) when compared to cases with benign pathology (kappa = 0.52). Nuclear characteristics were appreciated with a better agreement than other parameters. Modified UFPAP stain appears to be quick, reliable, cost-effective alternative in cytology, especially for detecting malignant cells in smears with low cellularity. Its specific advantage is robust nuclear staining against a clear background.