Platelet-derived acid phosphatase isoenzyme in the serum in thrombocythemia.

Acid phosphatase is present in platelets and is released during the clotting process. In thrombocythemic conditions, this may increase serum enzymatic activity. An illustrative case in which the determination of plasma enzymatic activity suggested a platelet origin of elevated serum levels, confirmed by isoenzyme fractionation on disk polyacrylamide gel electrophoresis is presented. It is concluded that in the presence of thrombocytosis a plasma sample is preferable to a serum sample for determination of acid phosphatase activity.