Readers respond: further insight on amylase and lipase.
In our experience, increased amylase and lipase activities occur simultaneously in patients with acute pancreatitis, i.e., we have not observed cases where the amylase rises first. This might be expected, given that both enzymes originate from acinar cells of the exocrine pancreas and have roughly the same molecular weight (54-62 kDa and 46-56 kDa, respectively). In the 4th (2006) edition of Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, Panteghini, et al, [it is] stated that a rise in amylase typically occurs within five to eight hours after onset, while lipase rises within four to eight hours. (1)
The older medical literature indeed describes amylase as the earlier marker of the two enzymes. (2) However, contemporary lipase assays now contain colipase and bile salts that increase the analytical sensitivity of lipase assays. Given that lipase remains increased for longer periods of time and has higher clinical specificity, as Dr. Buettner noted, we and others (3), (4) recognize that lipase is the superior test and amylase provides redundant clinical information. At the San Francisco General Hospital Clinical Chemistry Laboratory, we have recently eliminated serum amylase from the laboratory menu as a cost-savings measure. Although the savings in reagent costs have been modest, there have been no clinical issues raised by our colleagues. On the other hand, we believe removing amylase and other older tests contributes to better cost-effective medical practices.
--Alan H.B. Wu, PhD Chief, Clinical Chemistry Laboratory San Francisco General Hospital; Professor, Laboratory Medicine University of California, San Francisco and Susan Gross, BS, MS Senior Supervisor Clinical Chemistry Laboratory San Francisco General Hospital
Dan Baer's response: Dr. Louis Buettner and I appreciate Dr. Wu's letter and thank him for his insights.
(1.) Panteghini M, Bais R, van Solinge WW. Enzymes. In: Burtis CA, Ashwood ER, Bruns DE, eds. Tietz Text book of Clinical Chemistry and Molecular Diagnostics. 4th ed. St. Louis, MO: Elsevier Saunders;2006:616-621.
(2.) Kowlessar OD. Diseases of the Pancreas. In: Beeson PB, McDermott W, eds. Cecil-Loeb Textbook of Medicine. 4th ed. Philadelphia, PA: Saunders;1967:903.
(3.) Viel JF, Foucault P, Bureau F, et al. Combined diagnostic value of biochemical markers in acute pancreatitis. Clin Chem Acta. 1990;189:191-198.
(4.) Werner M, Steinberg WM, Pauley C. Strategic use of individual and combined enzyme indicators for acute pancreatitis analyzed by receiver-operating characteristics. Clin Chem. 1989;35:967-971.
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|Title Annotation:||Letters to the editor|
|Publication:||Medical Laboratory Observer|
|Article Type:||Letter to the Editor|
|Date:||Feb 1, 2006|
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