- Amylase, the pancreatic enzyme responsible for digesting carbohydrates, is the most common blood test for acute pancreatitis. It increases from 2 to 12 hours after the beginning of symptoms and peaks at 12 to 72 hours. It may rise to 5 to 10 times the normal level and will usually return to normal within a week. Amylase also may be monitored in patients with chronic pancreatitis; it will often be moderately elevated until the cells that produce it are destroyed, at which point blood levels may be decreased. It should be noted that amylase is an enzyme that has different forms called isoenzymes: P-amylase refers to that made by the pancreas and S-amylase refers to the form made by the salivary glands. Normally, a total amylase is requested. Sometimes, the isoenzymes are requested to distinguish pancreatic and non-pancreatic causes of increased amylase.
- Lipase is the pancreatic enzyme that, along with bile from the liver, digests fats. Its level increases in the blood within 4 to 8 hours of the beginning of an acute attack and peaks at 24 hours. Lipase is both more sensitive and specific than amylase for the diagnosis of acute pancreatitis. However, there are other sources of lipase in the digestive tract. For some assays that detect non-pancreatic lipase, milder elevations may occur with non-pancreatic disorders. In patients with pancreatitis, lipase may rise to several times its normal level and remains elevated longer than amylase. As cells are destroyed with chronic pancreatitis and as lipase production drops to less than 10% of the normal level, steatorrhea (fatty, foul-smelling stools) will form. As chronic pancreatitis progresses, amylase and lipase may be normal or decreased even during acute attacks.
- Trypsin is the pancreatic enzyme that digests proteins. Measurement of serum trypsin is thought to be the most sensitive blood test for pancreatitis, particularly chronic pancreatitis, but is not widely available and is not routinely used. The available test is variably identified as trypsinogen, trypsin-like immunoreactivity, or immunoreactive trypsin.
- Stool trypsin tests are used to check for pancreatic insufficiency and may be part of a work-up for chronic pancreatitis, including that due to cystic fibrosis.
Other tests that may be used to check for complications of acute pancreatitis include:
- Complete Blood Count (including white blood cell count)
- Comprehensive Metabolic Panel (including bilirubin, liver enzymes)
- C-Reactive Protein (a measure of inflammation)
Other tests that may be used to help diagnose and evaluate chronic pancreatitis include:
- Fecal fat
- Fecal pancreatic elastase
- Sweat (chloride) test for diagnosis of cystic fibrosis
- Molecular biology tests for genetic mutations such as those associated with cystic fibrosis
Non-laboratory tests may include:
- Abdominal ultrasound
- Endoscopic retrograde cholangiopancreatography (ERCP): a test that uses a flexible scope inserted through the mouth and threaded through the esophagus to allow the pancreas to be examined and to see and sometimes remove gallstones as well as look for abnormal cells and tissues
- Magnetic resonance cholangiopancreatography (MRCP): a type of magnetic resonance imaging (MRI) used to image the pancreas and bile ducts; often used before or instead of ERCP
- Computed tomography (CT) scan
- Secretin testing (not widely available) in which a tube is positioned in the duodenum to collect pancreatic secretions stimulated by intravenous (IV) administration of secretin. The amount of enzymes, such as lipase and trypsin, and bicarbonate in the pancreatic secretion is measured and compared to normal values.
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