A fecal elastase level test is the most sensitive and specific indirect test of pancreatic function. However, in the absence of testing a formed stool, routinely checking for exocrine pancreatic insufficiency in patients with chronic diarrhea using fecal elastase levels is unreliable. In patients with mild exocrine pancreatic insufficiency, diagnostic testing using fecal elastase levels has a lower sensitivity and specificity, which may result in an underestimation of exocrine pancreatic insufficiency.
Blood tests are an important component of the workup for suspected exocrine pancreatic insufficiency. Microcytic anemia due to iron deficiency or macrocytic anemia due to vitamin B12 or folate malabsorption may be revealed by a complete blood cell count. Additionally, serum iron, vitamin B12, and folate levels may help confirm the presence of malabsorption, and prothrombin time may be prolonged due to malabsorption of vitamin K, a fat-soluble vitamin.
A full malabsorption workup is required to distinguish exocrine pancreatic insufficiency from other causes of malabsorption. This may include fat absorption tests, a D-xylose test, a carbohydrate absorption test, a bile salt absorption test, a three-stage Schilling test, and the 13C-D-xylose breath test.
Abdominal imaging can be useful for identifying features of chronic pancreatitis, which is the most common cause of exocrine pancreatic insufficiency. It may be particularly important for patients with chronic pancreatitis who may not have the signs and symptoms of exocrine pancreatic insufficiency because fat maldigestion is not evident until pancreatic lipase secretion falls below 10% of normal.
Learn more about the workup of patients exocrine pancreatic insufficiency.
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Cite this: B.S. Anand. Fast Five Quiz: Exocrine Pancreatic Insufficiency - Medscape - May 04, 2020.