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Amylase - blood
Definition
Amylase is an enzyme that helps digest carbohydrates. It is produced in the pancreas and the glands that make saliva. When the pancreas is diseased or inflamed, amylase releases into the blood.
A test can be done to measure the level of this enzyme in your blood.
Amylase may also be measured with a urine test. See amylase - urine.
How the Test is Performed
A blood sample is needed. For information on how this is done, see: Venipuncture.
How to Prepare for the Test
No special preparation is needed. However, you should avoid alcohol before the test. The health care provider may ask you to stop taking drugs that may affect the test. NEVER stop taking any medications without first talking to your doctor.
Drugs that can increase amylase measurements include:
- Asparaginase
- Aspirin
- Birth control pills
- Cholinergic medications
- Ethacrynic acid
- Methyldopa
- Opiates (codeine, meperidine, morphine)
- Thiazide diuretics
How the Test Will Feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
This test is most often used to diagnose or monitor acute pancreatitis. It may also detect some digestive tract problems.
The test may also be done for the following conditions:
Normal Results
The normal range is 23 to 85 units per liter (U/L). Some laboratories give a range of 40 to 140 U/L.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
What Abnormal Results Mean
Increased blood amylase levels may occur due to:
- Acute pancreatitis
- Cancer of the pancreas, ovaries, or lungs
- Cholecystitis
- Gallbladder attack caused by disease
- Gastroenteritis (severe)
- Infection of the salivary glands (such as mumps) or a blockage
- Intestinal blockage
- Macroamylasemia
- Pancreatic or bile duct blockage
- Perforated ulcer
- Tubal pregnancy (may have burst open)
Decreased amylase levels may occur due to:
- Cancer of the pancreas
- Damage to the pancreas
- Kidney disease
- Toxemia of pregnancy
Risks
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Owyang C. Pancreatitis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 147.
Tenner S, Steinberg WM. Acute pancreatitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 58.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
