Cytology specimens can be fixed whilst wet with alcohol-based fixatives. Some are air-dried for staining with May-Grunwald-Giemsa.

Staining

Papanicolaou

The Papanicolaou stain is one of the most well-known cytology stains. It shows nuclear detail well and is used for most wet-fixed cytology preparations. Most cells will have blue-green cytoplasm on Pap stains, although keratinized cells stain pink-orange, and where thicker layers of non-keratinized cells are present these will usually appear more pink-orange.

Giemsa

May-Grunwald-Giemsa stain is typically used on air-dried samples and can be prepared rapidly. As the samples are air-dried, cells appear large on these preparations compared to the same cells seen on wet-fixed specimens. This method produces blue-purple staining of the cells.

H+E

This is used for cell block preparations. Some centres use H+E for wet-fixed cytology preparations.

Immunocytochemistry

This is often performed on a cell block preparation, or can be performed on other preparations such as Cytospins.