Abstract
Background: Adequate fixation is an essential pre-analytical step in pleural effusion cytology because it preserves cellular morphology and supports optimal Papanicolaou staining. Although 96% ethanol is commonly used as a wet fixative, 10% formal alcohol may provide an alternative when conventional alcohol fixation is less practical. However, comparative information regarding the staining quality of pleural effusion smears fixed with these two solutions remains limited.Objective: This study aimed to compare the staining quality of Papanicolaou-stained pleural effusion smears fixed with 96% ethanol and 10% formal alcohol.Methods: A descriptive comparative laboratory study was conducted using 20 pleural effusion specimens. The specimens were divided into two fixation groups: 96% ethanol (n=10) and 10% formal alcohol (n=10). Cytological smears were prepared from pleural effusion sediments, fixed according to the assigned fixation group, and stained using the conventional Papanicolaou method. Staining quality was evaluated microscopically based on three parameters: nuclear–cytoplasmic contrast, background cleanliness, and staining uniformity. Data were analyzed descriptively using frequencies and percentages.Results: All specimens in both fixation groups demonstrated good overall staining quality (100%). Nuclear–cytoplasmic contrast and staining uniformity were classified as good in all specimens in both groups (100%). Differences were observed in background cleanliness. Good background cleanliness was observed in 7 of 10 smears (70%) fixed with 96% ethanol and 5 of 10 smears (50%) fixed with 10% formal alcohol.Conclusion: Both 96% ethanol and 10% formal alcohol produced good overall staining quality in Papanicolaou-stained pleural effusion smears. The two fixatives showed comparable nuclear–cytoplasmic contrast and staining uniformity, whereas 96% ethanol produced a higher proportion of smears with good background cleanliness. Thus, 96% ethanol remains the preferred fixative when optimal background cleanliness is required, while 10% formal alcohol may be considered as an alternative for routine cytological preparation.