Pancreatic function tests

Pancreatic function tests

Pancreatic exocrine function can be assessed by directly measuring pancreatic secretion in response to a standardised stimulus. The stimulus to secretion can be physiological, e.g. ingestion of a test meal, as in the Lundh test, or pharmacolog - ical, e.g. intravenous injection of a hormone such as secretin triple-lumen tube so that the gastric and duodenal juices can be aspirated, and a non-absorbable marker such as polyethylene glycol is used to assess the completeness of the aspiration. The nitroblue tetrazolium–para-aminobenzoic acid (NBT–PABA) test provides an indirect measure of pancreatic function. The substance is administered orally and degraded in the gut by a pancreatic enzyme, and the breakdown product (PABA) is absorbed by the intestine and excreted in the urine; its urinary level is measured. The pancreolauryl test works on a similar principle. These tests are cheap and easy to perform but are non-specific, especially following gastrectomy and in conditions that may alter gastrointestinal transit and intestinal absorptive capacity . They are rarely used now in the clinical setting. Measurement of the enzyme elastase in stool is simple, specific and now used widely . A low level of faecal elastase indicates exocrine insu ffi ciency .