Direct comparability of results of measurements of catalytic
activity concentration of enzymes depends primarily on agree–
ment on the following:
1. Chemical Composition of the Reaction Mixture
2. Reaction Temperature (cf. Convertibility, below).
3. Units of Catalytic Activity Concentration.
1. In clinical enzymology, the rigorously defined IFCC Refe–
rence Methods take the place of the primary reference materi–
als used in the determination of non-enzyme analytes.
Whereas the procedures of the IFCC reference methods themsel–
ves considerably restrict their use as routine methods, it is
possible to describe a Simplified standard Adaptation of each
of these methods that readily permits its implementation as
an everyday routine method but still retains an "accuracy"
and precision close to that of the unmodified IFCC Reference
Method.
The present ECCLS standards for Enzyme Determination do not
represent a further set of "new" recommendations, but they
are rather a codification of sound, practical analytical pro–
cedures based on existing knowledge and practice.
They draw on the existing body of knowledge on enzyme methods
developed by the Expert Panel on Enzymes (EPEnz) of the IFCC
and by the National Enzyme Committees. They specify allowable
limits of procedural modifications in terms of performance
specifications to provide routine enzyme assay methods which
can readily be adopted in Eu ropean clinical laboratories.
Most of the procedural changes proposed represent minor vari–
ations that are a l ready rout ine practice in most countries.
Klinisk kemi
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Norden 2: suppl, /990
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