[A macromolecule capable of modifying CK-MB results and of inducing false acute myocardial infarction diagnosis].
OBJECTIVE
To evaluate the diagnostic value of CK-MB in acute myocardial infarction, to differentiate the relation between creatine phosphokinase (CPK), CK-MB and macro CK-BB (a macromolecule formed by an atypic CK-BB linked to an immunoglobulin) and to investigate the association of macro-BB with cancer.


METHODS
We studied 105 patients: 47 with various tumors; 8 with acute myocardial infarction and one control group with 50 persons without cardiac or oncologyc diseases. The CK-MB, CPK and macro CK-BB were measured in the serum of all patients and of the control group.


RESULTS
Among patients with cancer, 12 (25.6%) showed positive serum macro CK-MB. Two of them (16.6%) showed concomitant increase in CK-MB. All patients with increased serum macro CK-MB had malignant tumors.


CONCLUSIONS
The CK-MB is a reliable test for the myocardial infarction, however, when this isozyme is increased in the presence of normal CPK value, it must be questioned the presence of macro CK-BB to avoid false positive results. The presence of macro CK-BB could be relationed with malignant disease, specially with carcinoma of the prostate.
de Almeida Camarozano
A C
AC
Hospital Prof Edmundo Vasconcelos, São Paulo.
Gaspar Henriques
L M
LM
D000328:Adult; D015415:Biomarkers; D003402:Creatine Kinase / Q000097:blood*; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009369:Neoplasms / Q000175:diagnosis*; D011247:Pregnancy
D015415:Biomarkers; D007527:Isoenzymes; D003402:Creatine Kinase
Uma macromolécula capaz de alterar o resultado da CK-MB e induzir ao erro no diagnóstico de infarto agudo do miocárdio.