[Creatine kinase: reference values and clinical aspects of the revised standard method (author's transl)]

Reference values for the revised standard method for determining N-acetylcysteine (NAC) activated creatine kinase (CK) activity in serum are presented, based on samples from 432 out-patients and 423 in-patients of either sex. CK activity was not age-related. The suggested range of normal values for serum CK activity, measured by the revised standard method at + 25 degree C, is 10--70U/l for females and 10--80U/l for males. Where an elevation of serum CK activity is of uncertain cause, the CK/GOT ratio had been recommended, additional to the CK-MB isoenzyme, for distinguishing between damage to heart and skeletal muscle. The significance of this ratio was checked with the revised standard CK method and the optimized GOT determination. The point of separation between myocardial and skeletal muscle damage is 10 by this methods. In order to use this ratio, total CK activity must be over 150 U/l and liver disease or secondary liver involvement must have been excluded. The CK/GOT ratio gains in importance through findings which limit the specificity of CK-MB as a purely myocardial (infarct)-specific isoenzyme.