Synonym

• Alpha amylase
• AML

Tubes

• Red top, tiger top, green top(heparin) tube
• 5 mL venous blood

Care of specimen

• Maintain at room temperature

Info

Amylase is a digestive enzyme that functions primarily in the digestion of complex carbohydrates. It is primarily formed by the pancreas and salivary glands, but is also present in other tissues including:

• Fallopian tube
• Lungs
• Thyroid
• Tonsils
• Various malignant neoplasms

The pancreatic and the salivary isoenzymes are the ones most commonly detected by the assay.

Clinical

Serum amylase assays have the following clinical utility:

• Aid in the diagnosis of acute pancreatitis
• Aid in the diagnosis of macroamylasemia
• Aid in the diagnosis of pancreatic duct obstruction
• Detect injury to the pancreas due to blunt trauma or surgery
• Exclude acute pancreatitis as a cause of acute abdominal pain

Additional information:

• In early acute pancreatitis, serum amylase levels start increasing 6-24 hours after onset. It often decreases after 3-7 days due to increased renal amylase excretion (Lipase will be useful in these situations).
• When normal amylase combines with high molecular weight protein immunoglobulin, macroamylase is formed which is characterized by high serum amylase
• Pancreatic amylase is tightly bound to the mucosa of the small intestine. Small bowel injury is often associated with elevated serum amylase.
• Patients with elevated serum amylase, in the absence of signs of pancreatic diseases, should undergo screening for celiac disease.
• When routine monitoring is being performed, the patient should abstain from alcohol for at least 24 hours before the test (alcohol consumption may result in elevations).
• For at least 2 hours before the test, no food or fluids, except water, should be taken.

Nl Result

Overview:

• In neonates, usually no amylase activity is detected.
• At about 2 months of age, measurable amylase activity is detected. It increases gradually and reaches adult values by age of 1 year.

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

High Result

High serum amylase concentration is called hyperamylasemia. It may occur in the following conditions:

• Increase in pancreatic amylase
• Pancreatic diseases
• Acute Pancreatitis
• Biliary Tract Disease
• Choledocholithiasis
• Chronic Pancreatitis
• Early Cystic Fibrosis
• Pancreatic Ascites
• Pancreatic Abscess
• Pancreatic Cancer
• Pancreatic Trauma
• Post ERCP
• Pseudocyst
• Gut diseases
• Appendicitis
• Celiac Disease
• Gastric Resection
• Intestinal Obstruction
• Mesenteric Infarct
• Perforated Bowel
• Peritonitis
• Other
• Abdominal Aortic aneurysm
• Burns
• Cerebral Trauma
• Hyperparathyroidism
• Postoperative State
• Increase in salivary amylase
• Salivary diseases
• Salivary gland calculi
• Salivary gland inflammation (e.g. Parotitis)
• Salivary gland radiation
• Salivary gland surgery
• Salivary gland trauma
• Female Genital tract
• Ectopic Pregnancy (Ruptured)
• Fallopian Cysts
• Ovarian Cysts
• Salpingitis
• Tubo-ovarian Abscess
• Malignancies
• Ectopic production (especially esophagus, lungs and ovary)
• Other
• Anorexia Nervosa
• Bulimia
• Nonketotic Acidosis
• Pneumonia
• Increase in both salivary and pancreatic isoenzymes
• Liver diseases
• Cirrhosis
• Hepatitis
• Renal Failure
• Increase in either salivary or pancreatic isoenzyme
• Alcoholism
• Others
• Ketoacidosis
• Extracorporeal Circulation
• Increase in macroamylase
• Macroamylasemia (high serum amylase but low urine amylase)

Drugs that increase the serum amylase levels include:

• Asparaginase
• Aspirin
• Azathioprine
• Captopril
• Cholinergic agents
• Cimetidine
• Clofibrate
• Corticosteroids
• Diuretics (Loop & Thiazide)
• Estrogens
• Ethacrynic acid
• Ibuprofen
• Indomethacin
• Methyldopa
• Nitrofurantoin
• Opiates
• Oral contraceptives
• Pentamidine
• Pentazocine
• Sulfonamides
• Tetracycline
• Valproic acid
• Zalcitabine

Normal or high serum amylase levels may be seen in:

• Relapsing or chronic pancreatitis
• Alcoholism
• Pregnancy

Low Result

Low levels of serum amylase may be seen in the following conditions

• Cystic fibrosis (advanced)
• Eclampsia
• Hepatic disease or Cirrhosis
• Hypertriglyceridemia (may be falsely low)
• Pancreatic cancer
• Pancreatectomy
• Pancreatic insufficiency
• Renal disease

Drugs that decrease the serum amylase levels include:

• Anabolic steroids
• Citrates
• Fluorides
• Oxalates

References

• Carroccio A et al. Unexplained elevated serum pancreatic enzymes: a reason to suspect celiac disease.Clin Gastroenterol Hepatol 2006 Apr;4(4):455-9.
• Deprettere AJR et al. Disappearance of Macroamylasemia in a Celiac Patient After Treatment With a Gluten-Free Diet. Journal of Pediatric Gastroenterology and Nutrition. September 2001;33(3):346-8.
• Laboratory Corporation of America® Amylase, Serum. [Homepage on the internet] ©2003[cited 2006 August 2] Available from http://www.labcorp.com/datasets/labcorp/html/chapter/mono/pr000900.htm
• Labtestsonline[Homepage on internet] ©2001-2006 [updated 2002 Nov 26;cited 2006 July 1] Available from http://labtestsonline.org/understanding/analytes/amylase/test.html
• MedlinePlus[Homepage on internet]c2005 [updated 2005 Feb 14;cited 2006 July 1] Available from http://www.nlm.nih.gov/medlineplus/ency/article/003464.htm
• Voudris K et al. Serum total amylase, pancreatic amylase and lipase activities in epileptic children treated with sodium valproate monotherapy. Brain Dev. 2006 May 24; [Epub ahead of print]