[A study of the enzymes in citrated blood plasma]

Elevated blood serum, vs. the plasma, levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and gamma-glutamyl transferase activities are explained by these enzymes discharge from red cells into the liquid fraction of the blood during its in vitro coagulation. To eliminate the "tube" hemolysis, the authors recommend measurements of these enzymes activities in the blood citrate plasma.