Comparative Cytomorphologic Performance of Rehydrated Air-Dried and Conventional Papanicolaou Staining in Cervical Smears in a Prospective Paired Study

Background: Immediate alcohol fixation is central to conventional Papanicolaou staining (CPAP) but can be difficult to maintain in high-volume and peripheral settings.Controlled air drying followed by saline rehydration may reduce erythrocyte-related obscuration while preserving epithelial morphology.Objective: To compare the paired cytomorphologic performance of rehydrated air-dried Papanicolaou staining (RADPS) with CPAP in cervical smears.Methods: This prospective, single-center study analyzed 100 women with complete paired CPAP and RADPS preparations.Coded assessments compared adequacy, background, cellularity, cytoplasmic staining, cell borders, nuclear borders, chromatin, and six-month preservation.Exact McNemar and Stuart-Maxwell tests, matched odds ratios, bootstrap confidence intervals (CIs), agreement statistics, and Holm multiplicity correction were used.Results: Satisfactory smears increased from 90 (90.0%) with CPAP to 99 (99.0%) with RADPS, a paired increase of 9.0 percentage points (95% bias-corrected and accelerated (BCa) CI: 4.0-16.0;exact p = 0.004).Clear backgrounds increased from 38 (38.0%) to 95 (95.0%), and distinct cell borders increased from 74 (74.0%) to 98 (98.0%) (Holm-adjusted p < 0.001 for both).The remaining secondary cytomorphologic outcomes were not statistically significant after adjustment.Broad cytologic-category agreement was 88 (88.0%) (Cohen kappa: 0.664; Gwet agreement coefficient 1 (AC1): 0.864).The exploratory seven-item technical-quality score increased by 0.98 criteria (95% BCa CI: 0.77-1.23;p < 0.001).Conclusion: In this 100-participant paired analysis, RADPS was associated with higher smear adequacy, cleaner backgrounds, and better cell-border definition.The findings support RADPS as a technical alternative when immediate wet fixation is difficult, while diagnostic superiority remains unproven.