Advancing Pap Smear Cytology: Effects of the Wash Technique on Sample Adequacy and Diagnostic Reliability

Abstract

Cervical cancer is one of the most preventable cancers, yet many women still face delayed or missed diagnoses because of something as simple as an “unsatisfactory” Pap smear result. When a sample is reported as inadequate, often due to gel, blood, or inflammation, the patient may need to return for another test, creating anxiety, extra costs, and possible delays in detecting disease. To overcome this problem, laboratories have started using a simple but promising approach known as the wash technique. In this method, inadequate samples are gently rinsed in a mild acetic acid solution and reprocessed, allowing hidden cells to be recovered and reducing background debris. We retrospectively reviewed 645 Thin Prep Pap smears that underwent the wash protocol at King Fahad Armed Forces Hospital between 2020 and 2024. After reprocessing, 69.77% of cases were satisfactory, with 83.56% reported as NILM and 16.44% showing epithelial abnormalities, including ASC-US, LSIL, HSIL, and AGC. No squamous cell carcinoma or adenocarcinoma were detected. We conclude that the wash technique substantially improves Pap smear adequacy, salvaging the majority of initially unsatisfactory cases and enabling the detection of clinically relevant abnormalities. Unsatisfactory rates increased with advancing age, highlighting the need for age-aware approaches in cytology practice. Incorporating wash protocols into routine cytology practice may reduce repeat testing, minimize diagnostic delays, and strengthen the effectiveness of cervical cancer screening programs.