Effectiveness of modified Papanicolaou staining method used in a Sri Lankan government sector laboratory: a cost-effective method for resource limited settings

Background and Objective: The study investigates the effectiveness of a modified Papanicolaou staining method for cervical screening, currently practiced at District General Hospital Matara (DGHM), Sri Lanka, as the conventional method requires a high amount of alcohol.
Materials and Methods: A cross-sectional study was conducted from September to November 2023 in the histopathology laboratory at DGHM. A total of 161 cervical smears were collected from Medical Officer of Health (MOH) areas in Matara. Paired smears were stained using both the conventional and modified Pap methods. The modified method involved replacing the alcohol series for hydration with 70% alcohol. After staining with Harris' haematoxylin and rinsing with tap water, the differentiation step in 0.5% HCl and dehydration step with an alcohol series were omitted. Tap water replaced the use of 95% alcohol for rinsing after staining with OG6 and EA50. Smears were air-dried, mounted, and blindly evaluated by the primary investigator, two cyto screeners, and a consultant histopathologist using a standardized scoring system. A quality index was calculated for each method.
Results: Out of 152 satisfactory paired smears, 98.7% of conventionally stained and 96.7% of modified-method smears showed distinct cytoplasmic borders. Satisfactory cytoplasmic staining was observed in 60.5% and 57.2% of conventional and modified smears, respectively. All smears showed distinct nuclear borders and crisp chromatin staining. There was no statistically significant difference in cytomorphological quality (p > 0.05). The quality index for the modified and conventional methods was 0.911 and 0.932, respectively. The modified method reduced alcohol use by 80%, resulting in significant cost savings.
Conclusion: The modified Pap staining method is a cost-effective, simpler alternative suitable for cervical cytology in resource-limited settings without compromising diagnostic quality.