Preservation of faecal specimens

Stools sent to the laboratory by post should be fixed in 10% formalin or SAF fixative (Yang and Scholten 1977) to preserve parasite morphology and prevent growth of yeast and moulds. Formalin (10%): mix 100ml formaldehyde solution (usually 37-40%) with 900ml distilled water. Store at RT. Shelf life, 2 years. For use, mix one part faeces with three parts formalin to make a homogenous suspension.

SAF fixative: dissolve 15g sodium acetate in some distilled water. Add 20ml glacial acetic acid, 40ml formaldehyde solution and distilled water to 1l. Store at RT; shelf life, 2 years. Use as for 10% formalin.

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