Tissue samples should be placed into 10% buffered formalin using a volume roughly equivalent to 20 times the volume of the tissue sample to ensure adequate fixation. Fixation must be carried out for a minimum of 24 hours, it would be helpful if the time and date when the sample was placed into fixative can be given.

Formalin fumes are rapidly penetrating. They alter the staining and morphology of haematology and cytology specimens. Keep open formalin containers away from these specimens even if opened momentarily.

Cytological samples can be collected by imprinting, swabbing, scraping and/or performing a fine-needle aspiration of the lesion.

Direct smears for cytological examination should be air dried and not fixed or cover slipped.

Fluid specimens should be placed immediately in EDTA tubes to prevent clot formation. If the fluid will be in transit longer than 24 hours, a direct slide preparation should be made to accompany the tube.

Touch imprints can be helpful adjunct to the histological examination of formalin-fixed tissues. Formalin vapours can alter the staining characteristics of touch imprints drastically. When touch imprints accompany formalin-fixed tissues, they should be placed in their own air-tight container.