Evaluation of a direct alpha-amylase assay using 2-chloro-4-nitrophenyl-alpha-D-maltotrioside

Clin Chem Lab Med. Nov-Dec 1999;37(11-12):1053-62. doi: 10.1515/CCLM.1999.154.


We present the adaptation of an IFCC method for alpha-amylase using 2-chloro-4-nitro-phenyl-alpha-D-maltotrio-side as substrate (1) suited for routine work at 37 degrees C. In the assay, a constant proportion of substrate, i. e. 92%, is directly converted to 2-chloro-4-nitrophenol and maltotriose. The method is based on multi- and univariate optimization leading to following measurement conditions: substrate, 2.25 mmol/l; chloride, 310 mmol/l; calcium 5.0 mmol/l; 4-morpholinoethanesulphonic acid, 50 mmol/l; pH 6.28. The assay may be carried out manually or by mechanized procedures, with substrate or sample start, and it shows these analytical properties in measuring amylase activity of sera: no lag phase, detection limit 2.9 U/l, linear range < or = 820 U/l (for 300 s) or < or = 1450 U/l (for 120 s of measurement), and total manual imprecision 3.2% (CV) at 46 U/l. Bilirubin < or = 630 micromol/l, haemoglobin < or =6 g/l, triacylglycerols < or =30 mmol/l, heparin < or =100 kU/l, and glucose < or =120 mmol/l do not interfere. For adults, we established a preliminary 0.95-reference interval of 30-90 U/l not dependent on sex or age. A close association with the IFCC method demonstrates the reliable transfer of its measurement conditions to a robust routine method with minimal changes.

MeSH terms

  • Adult
  • Evaluation Studies as Topic
  • Humans
  • Kinetics
  • Reproducibility of Results
  • Spectrum Analysis
  • Trisaccharides / chemistry*
  • alpha-Amylases / analysis*
  • alpha-Amylases / metabolism


  • Trisaccharides
  • 2-chloro-4-nitrophenylmaltotrioside
  • alpha-Amylases