Defining the Accuracy of Secretin Pancreatic Function Testing in Patients With Suspected Early Chronic Pancreatitis

OBJECTIVES: The diagnosis of chronic pancreatitis in patients with characteristic symptoms but normal pancreatic imaging is challenging. Assessment of pancreatic function through secretin pancreatic function testing (SPFT) has been advocated in this setting, but its diagnostic accuracy is not fully known. METHODS: This was a retrospective review of patients who received SPFT at our tertiary care institution between January 1995 and December 2008 for suspected chronic pancreatitis. For all patients, medical records were reviewed for evidence of subsequent development of chronic pancreatitis by imaging and/or pathology. Patients were then categorized as "true positive" or "true negative" for chronic pancreatitis based on follow-up imaging or histologic evidence. RESULTS: In all, 116 patients underwent SPFT. Of the 27 patients who tested positive, 7 were lost to follow-up. Of the remaining 20 SPFT-positive patients, 9 (45%) developed radiologic or histologic evidence of chronic pancreatitis after a median of 4 years (1-11 years). Of the 89 patients who had negative SPFT testing, 19 were lost to follow-up. Of the remaining 70 patients, 2 were eventually diagnosed with chronic pancreatitis based on subsequent imaging/histology after a median follow-up period of 7 years (3-11 years). The sensitivity of the SPFT in diagnosing chronic pancreatitis was 82% with a specificity of 86%. The positive predictive value (PPV) of chronic pancreatitis was 45% with a negative predictive value (NPV) of 97%. CONCLUSIONS: In patients with suspected early chronic pancreatitis and normal pancreatic imaging, SPFT is highly accurate at ruling out early chronic pancreatitis with a NPV of 97%