Abstract
The determination of α-amylase activity in serum, urine or other body fluids is widely used in clinical laboratory for the diagnosis of pancreatic disorders. We review the various laboratory methods including the advocated ones as well as the advanced or proposed ones. We learned from a recent survey of clinical laboratories that half of the participants used the amyloclastic methods and 40% used the methods involving dye-labeled starches. Perhaps both methods are convenient, but the former is not a strictly linear reaction, and absorbance peak of starch-iodine color complex shifts as hydrolysis of starch substrate proceeds. The latter is rapid and precise, but the costs of the substrates which can be obtained from commercial sources are expensive and furthermore, the results do not correlate well with those from other major methods. Kinetic methods have been accepted increasingly. These methods involve several coupled enzyme systems or different defined substrates and are more sensitive and have better linearlity of response to enzymatic activity. More advanced techniques involving chromogenic substrates with or without coupled enzyme reaction have been proposed, in which amylase activity would be measured more directly and probably free from the interferences owing to endogeneous glucose or maltose. Many challenges have been given to standardize the assay method of a-amylase activity in clinical chemistry, and much efforts are being made to provide the reference method and the reference material as well.
