Cytomorphologic Analysis of Wet and Spray Fixation Methods in Oral Exfoliative Cytology

Abstract

For a long time, oral exfoliative cytology (OEC) has been implemented as an effective preliminary diagnostic tool for pathological lesions and various methods for fixation of the cytology specimens have been studied. The present study was undertaken to compare the efficacy between the wet and spray type of fixation methods for Papanicolaou (PAP) stained oral cytosmears. The study comprised of 45 healthy subjects in the age group of 20-25 yrs. For each subject, two smears were collected from the buccal mucosa and subjected to wet and spray fixation methods respectively. Both the smears were stained using a commercial Rapid Pap Kit. Smears were observed microscopically and evaluated for cytomorphological features involving uniformity of staining, cellular morphology, nuclear morphology, cellular staining, nuclear staining and presence of impurities. Comparisons were made between the two methods of fixation and statistically analysed using McNemar non-parametric test. Cells were evenly distributed in wet-fixed smears (n=38, 95%) compared to spray fixed smears (n=19, 47.5%). Wet-fixed smears showed lesser impurities (n=13, 32.5%) than spray fixed smears (n=27, 67.5%).  However, other parameters such as cytological and nuclear morphology, staining of cytoplasm and nucleus were found to be not significant when compared between the two methods of fixation (p<0.05). The study shows that wet-fixed smears have better cellular distribution and relatively fewer impurities when compared to the spray fixed smears. The method of wet-fixed smears may be used as an alternative to spray fixed smears. A larger sample size may be required for further validation.