Interlaboratory study of the IFCC method for alanine aminotransferase performed with use of a partly purified reference material.
We present the results of a study on performance of a reference material for alanine aminotransferase (ALT, EC 2.6.1.2) and the corresponding IFCC-approved method in an interlaboratory trial involving 13 laboratories. The ALT material was partly purified from pig heart (specific activity, 150 kU/g) and was essentially free of six potentially contaminating enzyme activities, including aspartate aminotransferase (EC 2.6.1.1). The partly purified ALT was lyophilized in a triethanolamine-buffered matrix, pH 6.4, containing bovine serum albumin and saccharose. Under these conditions, the predicted yearly loss of activity was 0.02% at 4 degrees C and < 0.01% at -20 degrees C. The final blank-corrected results of the accepted set of data gave a mean (SD) of 128.5 (5.1) U/L. The among-laboratory SD was 4.6 U/L and the within-laboratory SD was 2.0 U/L. The certified ALT catalytic concentration in the reconstituted material was 129 U/L with a 0.95 confidence interval of +/- 4 U/L.
Schiele
F
F
Laboratoire du Centre de Médecine Préventive et Centre du Médicament, UA CNRS No 597, Nancy, France.
Muller
J
J
Colinet
E
E
Siest
G
G
Arzoglou
P
P
Brettschneider
H
H
Calam
D H
DH
Ceriotti
F
F
Férard
G
G
Frei
J
J
D000410:Alanine Transaminase / Q000097:blood* / Q000378:metabolism / Q000592:standards*; D000818:Animals; D002384:Catalysis; D004340:Drug Contamination; D004795:Enzyme Stability; D005612:Freeze Drying; D006801:Humans; D007753:Laboratories / Q000592:standards*; D009206:Myocardium / Q000201:enzymology; D011786:Quality Control; D011933:Reagent Kits, Diagnostic / Q000592:standards; D012015:Reference Standards; D013053:Spectrophotometry / Q000592:standards; D013379:Substrate Specificity; D013552:Swine
D011933:Reagent Kits, Diagnostic; D000410:Alanine Transaminase