Evaluation of a colorimetric test for the determination of alpha-amylase with p-nitrophenylheptaoside as substrate.
A continuous method for the determination of alpha-amylase activity with a defined substrate has been published by Rauscher et al. in Berichte der Osterreichischen Gesellschaft für Klinische Chemie 4, 150 (1981). It offers the following advantages: good practicability, easy adaptation to analysers and short incubation time. Twenty-one laboratories took part in a multicentric study on this method, working with different instruments and manual procedures at three temperatures. Additionally, all laboratories participated in a laboratory improvement program, in order to discriminate systematic from accidental errors. Data on imprecision, linearity, interferences and comparability of the method have been presented at a workshop. The resulting coefficients of variation for imprecision in series as well as from day to day were 0.6-6.3% and 1.3-7.7%, respectively. No interferences from bilirubin, glucose, maltose and 37 selected drugs were found. The results from the described method correlate well with those from an UV-test (substrate: maltoheptaose); compared with other methods, however, the expected systematic deviations were observed. Reference values for 25, 30 and 37 degrees C are indicated in this report.
D003124:Colorimetry / Q000379:methods; D004355:Drug Stability; D005960:Glucosides / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007202:Indicators and Reagents; D010084:Oxidation-Reduction; D011933:Reagent Kits, Diagnostic; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013379:Substrate Specificity; D013696:Temperature; D000516:alpha-Amylases / Q000097:blood*
D005960:Glucosides; D006027:Glycosides; D006454:Hemoglobins; D007202:Indicators and Reagents; D011933:Reagent Kits, Diagnostic; C036167:4-nitrophenyl maltoheptaoside; D000516:alpha-Amylases