Role of roswell park memorial institute media in preservation of cellularity and cell morphology in fluid samples: A cross‑sectional study

Background: Fluid cytology is an important for evaluating benign, inflammatory, infectious, and malignant conditions through examination of body fluids such as pleural, peritoneal, and cerebrospinal fluid. Accurate diagnosis depends on preservation of cellularity and cell morphology from collection to processing. Delay in transport or processing leads to cellular degeneration and reduced diagnostic accuracy. RPMI medium has been studied as a useful preservation medium because it helps maintain cellular integrity and morphology.
Aim: To study the role of RPMI medium in preserving cell morphology and cellularity in fluid samples.
Materials and Methods: This cross-sectional comparative observational study was conducted in the Department of Pathology, Rohilkhand Medical College and Hospital, Bareilly, from April 2024 to March 2025. A total of 144 fluid samples were included. Each sample was divided into two parts—one processed routinely and the other preserved in RPMI medium. Both were compared for cellularity, nuclear and cytoplasmic preservation, background clarity, degenerative changes, and contamination using standard cytological methods.
Results: RPMI-preserved samples showed better cellular preservation compared with routine processing. Adequate cellularity was observed in 87.5% of RPMI-preserved samples compared to 63.9% of routine samples. Nuclear and cytoplasmic details were also better preserved. Degenerative changes and bacterial contamination were lower in RPMI-treated samples, resulting in improved smear quality and better diagnostic interpretation.
Conclusion: RPMI medium is an effective preservation medium for fluid cytology specimens. It improves cellularity and morphology and may enhance diagnostic accuracy, especially in delayed or transported samples.