The diagnosis of chronic pancreatitis is typically based on tests on pancreatic structure and function, as direct biopsy of the pancreas is considered excessively risky. Serum amylase and lipase may or may not be moderately elevated in cases of chronic pancreatitis, owing to the uncertain levels of productive cell damage, though elevated lipase is the more likely found of the two. Amylase and lipase are nearly always found elevated in the acute condition along with an elevated CRP inflammatory marker that is broadly in line with the severity of the condition. A secretin stimulation test is considered the gold standard functional test for diagnosis of chronic pancreatitis but not often used clinically. The observation that bi-carbonate production is impaired early in chronic pancreatitis has led to the rationale of use of this test in early stages of disease (sensitivity of 95%). Other common tests used to determine chronic pancreatitis are faecal elastase measurement in stool, serum trypsinogen, Computed tomography (CT), ultrasound, EUS, MRI, ERCP and MRCP. Pancreatic calcification can often be seen on plain abdominal X-rays, as well as CT scans.
There are other non-specific laboratory studies useful in diagnosis of chronic pancreatitis. Serum bilirubin and alkaline phosphatase can be elevated, indicating stricturing of the common bile duct due to edema, fibrosis or cancer. When the chronic pancreatitis is due to an autoimmune process, elevations in ESR, IgG4, rheumatoid factor, ANA and antismooth muscle antibody may be seen. The common symptom of chronic pancreatitis, steatorrhea, can be diagnosed by two different studies: Sudan chemical staining of feces or fecal fat excretion of 7 grams or more over a 24hr period on a 100g fat diet. To check for pancreatic exocrine dysfunction, the most sensitive and specific test is the measurement of fecal elastase, which can be done with a single stool sample, and a value of less than 200 ug/g indicates pancreatic insufficiency.
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