Use of Absolute Alcohol in Preservation of Cell Morphology in Fluid Cytology at Various Temperatures: A Cross-sectional Study

Abstract

Introduction: Fluid cytology and the examination of malignant cells play an important role in the treatment of critical cases. The Department of Pathology (Cytopathology laboratory) receives samples for fluid cytology and examines malignant cells, reporting the White Blood Cell (WBC) count in the received fluid and the morphological findings of the cells examined on smears. Degeneration of cells in these body fluid samples, especially if the samples are not stored under proper conditions, is a common problem faced by many laboratories. Even overnight storage (12 hours) of these body fluids at temperatures of 4-8ºC (domestic refrigerators) may still cause some degree of degenerative changes. This becomes problematic in cytopathological reporting of body fluids, particularly when the samples are limited in amount or are from areas that cannot be re-aspirated {e.g., Cerebrospinal Fluid (CSF)}. While alcohol is a common fixative used for cell fixation in cytopathology, it is rarely used for fixing cells in fluid samples. Aim: To test the usage of absolute alcohol as a fixative in body fluid samples received in the cytopathology laboratory, which have been stored for 12 hours at two temperatures: room temperature and 4-8ºC. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at Subharti Medical College, Meerut, Uttar Pradesh, India. The study was conducted over the periods of two months, from February 2022 to March 2022. A total of 100 body fluid samples (including CSF, ascitic fluid, pleural fluids, etc.) sent for routine workup to the cytopathology laboratory were included in the study. Each body fluid sample (1 mL) was taken in two test tubes, and four drops of 100% (absolute) alcohol were added to both test tubes. The mixture of body fluid and absolute alcohol was then gently shaken, and one set of test tubes was kept at room temperature while the other set was kept at 4-8ºC. The data was tabulated in an MS Excel worksheet, and basic statistical analysis was performed. Results: The age range of cases whose samples were analysed was from one-week-old neonates to 65-year-old adults. The total number of fluid samples was 100, including 42 CSF samples, 23 ascitic fluid samples, 18 pleural fluid samples, and 17 Bronchoalveolar Lavage (BAL) fluid samples. Out of the 42 CSF samples, 15 showed preservation of morphology when the alcohol-body fluid mixture was kept at room temperature, while 22 cases showed preservation of the same mixture at 4-8ºC. Some samples showed no preservation (5 CSF), the reasons for which are discussed below. All the examined body fluids showed better preservation with alcohol at 4-8ºC. Conclusion: The addition of absolute alcohol as a fixative in fluids helps preserve the cytomorphological features of cells and provides better preservation for the diagnosis of fluid samples.

Keywords

• cytomorphological features
• degenerative changes
• malignant cells
• white blood cells