Variation of disaccharidase activities in duodenal biopsy specimens.

Multiple biopsy specimens were taken from the duodenal cap and/or from the descending part of the duodenum in patients admitted for routine upper endoscopy, to determine the degree of variation in disaccharidase activity. Four specimens were taken from each site and assayed in pairs. The mean coefficients of variation (CV) of enzymatic activities between duplicate measurements in the same pair of specimens were less than 3.5% and between two pairs of biopsies about 30%. The large variation in disaccharidase activity between assays performed on simultaneously biopsied specimens from the same area of the bulb and the descending part of the duodenum in the same individual implies that single values for enzyme activity must be interpreted with caution.