Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Lipases are enzymes that hydrolyze glycerol esters of long-chain fatty acids and produce fatty acids and 2-acylglycerol. Bile salts and a cofactor, colipase, are required for full catalytic activity and greatest specificity. The pancreas is the primary source of serum lipase. Both lipase and colipase are synthesized in the pancreatic acinar cells and secreted by the pancreas in roughly equimolar amounts. Lipase is filtered and reabsorbed by the kidneys. Pancreatic injury results in increased serum lipase levels.
Investigating pancreatic disorders, usually pancreatitis
In pancreatitis, lipase becomes elevated at about the same time as amylase (in 4-8 hours). But lipase may rise to a greater extent and remain elevated much longer (7-10 days) than amylase.
Elevations 2 to 50 times the upper reference have been reported. The increase in serum lipase is not necessarily proportional to the severity of the attack. Normalization is not necessarily a sign of resolution.
In acute pancreatitis, normoamylasemia may occur in up to 20% of such patients. Likewise, the existence of hyperlipemia may cause a spurious normoamylasemia. For these reasons, it is suggested that the 2 assays complement and not exclude each other, and that both enzymes should be assayed.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Patients should be fasting before the specimen is drawn.
Collection tubes with glycerol-lubricated stoppers or tubes containing citrate, oxalate, or EDTA should not be used.
Certain drugs such as cholinergics and opiates may elevate serum lipase.
Renal disease may elevate the serum lipase.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
> or =16 years: 10-73 U/L
Reference values have not been established for patients that are <16 years of age.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Tietz Textbook of Clinical Chemistry. Edited by CA Burtis and ER Ashwood. Philadelphia, WB Saunders Company, 2001
2. Swaroop VS, Chari ST, Clain JE: Acute pancreatitis. JAMA 2004;291:2865-2868