Prolonged Duration of Air-Dry Fixation of Cervical Smears Produces Superior Cytomorphological Staining Quality over Conventional Wet-Fixed Smears.

Introduction: Immediate fixation of smears in 95% alcohol for Pap staining is commonly used for cytopathological diagnosis of cancers and other diseases. Few research studies have investigated the comparative outcomes of alcohol wet fixation and rehydration of air-dried smears, indicating that air-dried rehydrated (ARF) smears are viable alternative to wet-fixed (WF) smears. However, there are no or few investigations on the effects of long durations of air-drying fixation on cytomorphological staining quality.

Materials and methods: 124 cervical smears were obtained from the Family Planning Unit of Komfo Anokye Teaching Hospital in Kumasi, Ghana. Quadruple smears were WF and air-dried for 2 h, 4 h, and 8 h prior to rehydration with normal saline and fixation (ARF). All the smears were stained with Papanicolaou stain, examined microscopically for their cytomorphological features, and scored. Cytomorphological scores were statistically analyzed using SPSS software.

Results: No significant difference in cytolysis, cell border, nuclear border, chromatin, and cellularity between WF and ARF was observed. However, significant differences in cytoplasmic staining quality (p value <0.001) and the absence of RBCs (p value <0.001) were observed in the 4-h ARF. The absence of RBCs in the ARF smears rendered a clearer background than in the wet fixation.

Conclusions: ARF, Pap-stained smears showed comparably superior cytomorphological features to those of WF smears. The 8-h ARF smears produce crispy chromatin and excellent background, making them suitable for bloody cytological samples.