Papanicolaou staining of air-dried smears: value in rapid diagnosis

Air-dried material normally submitted for Diff-Quik (modified Romanowsky stain) was rehydrated in normal saline, then fixed for a short period in formol alcohol, before staining by a modified Papanicolaou technique. Staining was performed by a rapid manual technique (< 2 min) if urgent or routinely on an automatic stainer. Comparisons were made between wet-fixed Papanicolaou-stained specimens and air-dried Papanicolaou-stained material. Air-dried material stained after rehydration showed superior nuclear definition compared with wet-fixed material; the removal of erythrocytes enhanced the staining of the remaining epithelial cells.