Temporal stability of acetylcholinesterase staining in colonic and rectal neural tissue.

Confirmation of the clinical diagnosis of Hirschsprung's disease on standard rectal suction biopsy requires demonstration of aganglionosis in 60 adequate serial sections of submucosa. Positive staining for acetylcholinesterase (AChE), demonstrating an increase in nerve fibres within the lamina propria, muscularis mucosae, and subjacent submucosa, is a useful adjunctive test. In this study, sections of distal colonic muscularis propria and rectal mucosa were stained for AChE over a period of days following storage at 4 degrees C and at room temperature (15-20 degrees C). Positive staining of neural tissue was demonstrated in specimens stored at 4 degrees C for up to 14 days, at which time the experiment was discontinued due to tissue autolysis. Positive staining of the myenteric plexus in colonic specimens stored at room temperature also continued until tissue dissolution became marked at 5 days. This study has demonstrated stability of AChE staining of intestinal neural tissue in specimens stored at 4 degrees C for 14 days, which suggests that reliable staining for AChE should still be achievable if rectal biopsies are taken in clinics/hospitals without access to staining facilities, provided that tissues are transferred (fresh and moist, at 4 degrees C) to a reference laboratory for staining within several days of the biopsy procedure.