[Macro-creatine kinase: an interesting occurrence that can cause diagnostic mistake].
BACKGROUND
Macroenzymes have been known for a long time. Macro-creatine kinase is important among them, because it can cause serious diagnostic misunderstanding.


OBJECTIVE
The authors describe a case in which creatine kinase MB isoenzyme activity measured by immunoinhibition was much higher than total creatine kinase activity.


METHODS
The presence and type of possible macro-creatine kinase was examined by the authors with heat-stability test and electrophoresis.


RESULTS
Total creatine kinase and creatine kinase MB isoenzyme activity measured by immunoinhibition of macro-creatine kinase sample remained still unchanged, while activity of control samples decreased significantly. Macro-creatine kinase remained on the carrying point, while isoenzymes migrated accordingly in the other samples during electrophoresis.


CONCLUSIONS
Two types of macro-creatine kinase are known. In the first the BB isoenzyme of enzyme joint to immunoglobulin (mostly immunoglobulin G) and its presence may refer to autoimmune factors. The second type is a polymer of mitochondrial creatine kinase and appears in malignant tumours mainly. The presented case the clinic of the patient, the heat-stability test and the typical electrophoretic migration proved the presence of the second type.
Kovács
Ferenc
F
Markusovszky Kórház, Központi Laboratórium, Szombathely.
Dobos
András
A
D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis; D002637:Chest Pain / Q000201:enzymology* / Q000209:etiology*; D003402:Creatine Kinase / Q000097:blood*; D052279:Creatine Kinase, MB Form; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D004586:Electrophoresis; D004795:Enzyme Stability; D005598:Fractures, Spontaneous / Q000175:diagnosis*; D006361:Heating; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D008297:Male; D011655:Pulmonary Embolism / Q000175:diagnosis; D013249:Sternum
D007527:Isoenzymes; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form