O'Keefe SJD et al. (2007) Physiological evaluation of the severity of pancreatic exocrine dysfunction during endoscopy. Pancreas 35: 30–36

Measurement of exocrine secretion and 72-hour fecal fat output, the gold standard tests of pancreatic function, is time-consuming and difficult. O'Keefe et al. measured enzyme concentrations in pancreatic secretions sampled during upper gastrointestinal endoscopy as a rapid, alternative method for assessing pancreatic injury.

The study included 11 healthy controls and 22 patients diagnosed with severe (n = 7), moderate (n = 5) or mild (n = 10) chronic pancreatitis according to the results of radiological imaging. Pancreatic secretion was stimulated with an enteral liquid diet and samples were collected by periampullary aspiration. A significant positive correlation was observed between trypsin concentrations in samples aspirated during endoscopy and trypsin concentrations secreted during a conventional 2-hour diet-stimulated pancreatic trypsin secretion and synthesis study. Trypsin secretion rates were significantly reduced in all pancreatitis patients and there was an imperfect correlation between rate reduction and the increasing severity of pancreatitis (i.e. 5 of the 7 patients with severe pancreatitis had trypsin secretion rates below the 90% reduction level associated with 'pancreatic insufficiency').

Measuring the trypsin concentration in samples obtained during endoscopy gave a more reliable indication of exocrine function than measuring the incorporation of isotope-labeled amino acids into secreted trypsin, with less variable results than a breath test measuring fat absorption. The authors suggest that measuring physiological stimulation of the pancreas by taking samples during endoscopy might, after further verification and refinement, become a useful tool for the diagnosis of chronic pancreatic dysfunction and the identification and prioritization of pancreatitis patients who would benefit from enzyme supplementation.