Macro CK type 2 as a cause of a false increase in CK-MB]

A case of CK-MB falsely elevated activity due to the presence of a macro CK is reported. The MB quantification showed inferior levels to the pre-established cut-off. The CK isoenzymes electrophoresis showed a type 2 macro CK. We suggest carrying out CK isoenzyme electrophoresis of CK-MB quantification in those cases in which the clinical course or ECG changes do not correlate with the CK-MB values, and in cases presenting low whole CK activity values along with high CK-MB values.