How to Diagnose Complex Carbohydrate Intolerance

Intolerance for complex carbohydrates is a malabsorption syndrome that can affect one or more steps required for the intestinal hydrolysis and transportation of carbohydrates. These syndromes are categorized into acquired and congenital types. Acquired syndromes such as lactose intolerance are the most common, and the most likely causes of congenital malabsorption are cystic fibrosis or Shwachman-Diamond syndrome. The following steps will show how to diagnose complex carbohydrate intolerance.

Instructions

• 1

  Obtain the patient's complete diet history categorized by the amount of ingested fluids, food and formula. Caregivers should record a detailed record of the patient's diet for at least one week.

• 2

  Record any gastrointestinal symptoms. These are typical in carbohydrate intolerance; recurring diarrhea is the most common. Other symptoms include abdominal pain ranging from mild to severe and vomiting.

• 3

  Look for systemic problems in the absence of gastrointestinal complaints. These most often affect children and include a failure to thrive, malnutrition, delayed puberty and poor weight gain.

• 4

  Measure the level of exhaled hydrogen. A malabsorption of carbohydrates increases the fermentation that occurs in the intestines, which liberates hydrogen gas. A concentration greater than 20 parts per million after ingesting carbohydrates indicates carbohydrate intolerance.

• 5

  Ingest a 5-g dose of D-xylose in a 10 percent solution. A positive result is indicated for children weighing more than 30 kg when less than 15 percent of the D-xylose is excreted in five hours. A serum level less than 25 mg/dL after one hour is considered positive for carbohydrate malabsorption in children weighing less than 30 kg.