Routine air drying of all smears prepared during fine needle aspiration and intraoperative cytology studies. An opportunity to practice a unified protocol offering the flexibility of choosing a variety of staining methods.

OBJECTIVE: To evaluate the possibility of routine use of air-dried smears (ADS) instead of wet-fixed smears (WFS). STUDY
DESIGN: Intraoperative cytology (IC) smears from 293 specimens and fine needle aspiration cytology (FNAC) smears from 118 cases were studied. Cytomorphology of ADS processed with our protocol for hematoxylin-eosin (HE) and Papanicolaou (PAP) staining after saline rehydration and postfixation in 95% ethanol with 5% acetic acid were compared with respectively stained WFS. Additional ADS were stored up to 72 hours at room temperature prior to HE, PAP and Diff-Quik (DQ) staining to evaluate the effects of postponing rehydration and postfixation. Special stains for fungi were also studied in four cases.
RESULTS: ADS were easy to prepare without air-drying artifact in the final HE- and PAP-stained smears. ADS were more cellular than WFS. Erythrocyte interference was frequent in WFS. HE and PAP staining of ADS stored up to 72 hours showed cytomorphology comparable to that of the similarly stained fresh smears. However, DQ staining was better if ADS were processed before 24 hours. ADS stained with special stain for fungi showed good morphology, similar to that in WFS.
CONCLUSION: All ADS showed results comparable to or better than WFS. ADS could be stored up to 72 hours before staining with HE and PAP. ADS offers the flexibility of selecting a variety of staining methods and is a practical alternative to WFS.