How Do I Interpret Disaccharid­ase Biopsy Results?

It may be beneficial for you to keep a copy of your or your child’s disaccharidases small bowel biopsy results. You can ask your doctor or the medical records department of your child’s medical practice for a copy.

Classic disaccharidases small bowel biopsy results associated with congenital sucrase-isomaltase deficiency (CSID) are as follows:

Your or your child’s levels of enzyme activity may differ from the list above, since there are individual differences in the severity of CSID and the degree to which each individual has problems digesting starches. Almost all those with CSID have decreased sucrase activity, even if such sucrase activity is not entirely absent.

Some individuals with CSID can tolerate typical amounts of starches in their diet. These individuals would most likely have normal levels of maltase and isomaltase (palatinase) activity. Some with CSID tolerate no dietary starches at all. These individuals would probably show low levels of maltase and isomaltase (palatinase) activity.

Knowing the level of lactase activity is also valuable, because dairy foods can be an important source of dietary calories for those with CSID who are not lactose intolerant. Some individuals with CSID have normal levels of lactase activity, while others are deficient in the lactase enzyme.

Knowing disaccharidase levels of activity can help in developing the best diet for each individual’s unique situation. Note that the chart below shows ranges for abnormal laboratory values in the United States only. Consult your individual lab report for what is considered abnormal for the particular lab that conducted your disaccharidase testing.

Sucrase: Abnormal range is less than 25 U*
Maltase: Abnormal range is less than 100 U*
Isomaltase (Palatinase): Abnormal range is less than 5 U*
Lactase: Abnormal range is less than 10 U*

*U, units; activity level may be reported as μM/min/g


  1. Nichols B, Adams B, Roach C, Ma C, Baker S. Frequency of sucrase deficiency in mucosal biopsies. J Pediatr Gastroenterol Nutr. 2012; 55(2):S28-S30. doi:10.1097/01.mpg.0000421405.42386.64
  2. Quest Diagnostics. Disaccharidases. Accessed February 13, 2020.