Page 36 - To keep a balance in disease specific intestinal insufficiency. Diagnostics and practical nutritional aspects - Nicolette Wierdsma

Chapter 3
Lundh test - Cholecystokinin (CCK)-secretin test
The Lundh test has been developed to measure the exocrine secretion of pancreatic digestive enzymes. It involves a test meal or hormonal induction (CCK-secretin) to stimulate the pancreas and to aspirate a part of the post- prandial pancreatic secretion (primarily trypsin). This makes it a specific exocrine pancreatic function test. It is operator dependent, time consuming and needs adequate, thus sometimes cumbersome, placement of a duodenal polyethylene suction tube near the papilla Vateri (5-7). The secretion of pancreatic enzymes may be decreased due to chronic pancreatic inflammation or obstructive processes (pancreatic cancer). In case of impaired GI transit time or due to digestion coordination problems, pancreatic function may be normal, but its functionality may be decreased, in a digestive way indistinguishable from exocrine dysfunction. The Lundh test is not regularly applied in daily practice. A 24 hours or 72 hours fecal fat content test may also be used, although less specifically, to assess exocrine pancreatic function (see below).
Lactose and fructose hydrogen breath tests
A disaccharide (lactose or fructose) intolerance is a common GI disorder, meaning that a subject has abdominal complaints due to lack of (functional) enzymes (maltase, isomaltase, lactase or fructase). However, (secondary) lactase deficiency is the most common disaccharidase deficiency, whereas fructase deficiency is rare. The principle of the breath test is that a subject ingests a fixed amount of the investigated disacharide, which remains undigested in the small intestine, and reaches the colon undigested. There, it is acted on and fermented by anaerobic colonic bacteria, producing hydrogen, which is subsequently absorbed and finally exhaled via the lungs. The exhaled breath is to be captured and analyzed at various time points following ingestion. Hydrogen breath test following ingestion of 50 g of lactose (or 20 g fructose), although associated with GI-symptoms, has been shown to have a higher sensitivity and specificity, if compared to the gold standard method (mucosal biopsy lactase activity) (8- 10). Studies with 25 g dose lactose are showing acceptable test characteristics. Breath tests are relatively easy to perform and predictive for enzyme deficiency, or disaccharide intolerance. Moreover breath tests (with glucose, lactose or (13C) xylose, and to a lesser extend fructose or the unabsorbed lactulose), represent attractive candidate substrates to identify Small Intestinal Bacterial Overgrowth (SIBO) as well when a biphasic pattern occurs. If patient produces approximately
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