Reference values for six enzymes in plasma from newborns and women at delivery.

We have determined the distribution in cord blood from healthy newborns of six enzymes: creatine kinase, lactate dehydrogenase, aspartate and alanine aminotransferase, alkaline phosphatase and gamma-glutamyltransferase. The concentration of enzymes were determined according to the methods recommended by the Scandinavian Committee on Enzymes. The distribution of isoenzymes and of enzymes in blood from women at delivery was investigated also. All distributions were positively skewed. The upper reference limits of cord blood exceeded those found in mother blood by a factor of eight for gamma-glutamyltransferase, and for lactate dehydrogenase and creatine kinase by a factor of two.