The Clinical Usefulness of Fecal Elastase-1 Test as an Exocrine Pancreatic Function Test for the Diagnosis of Chronic Pancreatitis / 대한소화기내시경학회지

BACKGROUND/AIMS: The quantitative analysis of fecal elastase-1 has been proposed as a noninvasive test for the examination of pancreatic exocrine function. Therefore, we evaluated the diagnostic value of fecal elastase-1 by comparing with endoscopic intraductal secretin test (IDST) which is used as a direct exocrine function test for the diagnosis of chronic pancreatitis. METHODS: Fecal elastase-1 concentrations were measured by ELISA in spot stool samples of 40 healthy control subjects, 21 patients with liver disease, and 12 patients with chronic pancreatitis diagnosed with endoscopic retrograde cholangiopancreatography (ERCP) and IDST. Chronic pancreatitis were then sub-classified into mild (I), moderate (II) and severe form (III), using the Cambridge classification according to ERCP finding. The linear regression analysis to evaluate the correlation between the concentration of fecal elastase-1 and IDST was performed during ERCP. The cut-off value of fecal elastase-1 to discriminate chronic pancreatitis was calculated based on receiver operating characteristic curve, and the clinical usefulness of fecal elastase-1 in the diagnosis of chronic pancreatitis was evaluated. RESULTS: There were several significant correlations between fecal elastase-1 and various parameters of IDST: pancreatic juice secretory volume (r=0.797, p<0.002), bicarbonate concentration (r=0.846, p<0.001), elastase-1 concentration in pancreatic juice (r=0.671, p<0.017), and amylase output (r=0.783, p<0.003). The mean value of fecal elastase-1 concentration in the patients with chronic pancreatitis (197+/-77microgram/g stool) was significantly lower than those in the healthy control subjects (815+/-133microgram/g stool) and patients with liver disease (594+/-206microgram/g stool) (p<0.05). The cutoff value of fecal elastase-1 to discriminate between the healthy control and chronic pancreatitis patients was 201microgram/g stool. With this cutoff value, the accuracy, sensitivity, and specificity of fecal elastase-1 to diagnose chronic pancreatitis were 78.8%, 67.7%, and 82.5%, respectively, compared to the morphological severity (the sensitivity of mild, moderate, and severe chronic pancreatitis was 33.3%, 66.7%, 83.3%, respectively). CONCLUSIONS: Measurement of fecal elastase-1 is a reliable and sensitive non-invasive test for the diagnosis of moderate to severe forms of chronic pancreatitis.

Usefulness of Intraductal Secretin Test in Assessing Exocrine Pancreatic Function in Patients with Chronic Pancreatitis / 대한소화기내시경학회지

BACKGROUND/AIMS: The duodenal intubation test (duodenal secretin test; DST) is now considered the 'gold standard' test of exocrine pancreatic function in detecting exocrine pancreatic dysfunction in patients with chronic pancreatitis. However, the DST has not been widely used, because it is time-consuming, invasive, and labor-intensive. On the other hand, intraductal secretin test (IDST) with endoscopic retrograde cannulation of the main pancreatic duct has been showed similar diagnostic efficiency compared with DST. We assessed the clinical usefulness of IDST and investigated parameters for assessing impaired pancreatic function of IDST. METHODS: Pure pancreatic juices were collected from 12 patients with chronic pancreatitis by endoscopic cannulation after a bolus intravenous injection of secretin 100 U, for 15min in three 5-min intervals. Five parameters of IDST were measured, and the sensitivity, specificity, and accuracy of IDST evaluated compared with ERP. RESULTS: When we regarded mean-1.5 SD as the lower limits of IDST, the diagnostic sensitivity, specificity, and accuracy of five parameters to detect chronic pancreatitis were 91.7-100%, 75-87.5%, and 85-90%, respectively. Among five parameters, pancreatic juice secretory volume, bicarbonate concentration, and amylase output showed the highest diagnostic accuracy, followed by lipase output and bicarbonate output. A 10-min collection showed as much information as a 15-min collection. CONCLUSIONS: 10-min intraductal secretin test is useful as the conventional exocrine pancreatic function test in detecting exocrine pancreatic dysfunction in patients with chronic pancreatitis and the most discriminatory parameters are pancreatic juice secretory volume, bicarbonate concentration, and amylase output.