title: Macrocreatine kinase in plasma: a cause for a false positive CK-MB immunoinhibition test.
abstract: The case of a patient with bronchial neoplasm is described. A non-typical form of creatine kinase found in the plasma gave rise to a false positive CK MB test by the immunoinhibition procedure. Electrophoresis on agarose gels beside a normal MM band showed an additional band between the MB and the MM band of a standard mixture. It could be shown by an immunoprecipitation test using precipitating antibodies against CK-MM and CK-BB that the creatine kinase of the abnormal band consists entirely of the MM-type, which after treatment with polyethylene glycol not only became susceptible to inhibiting anti-M antibodies, but also showed the electrophoretic motility of CK-MM. Gel filtration chromatography clearly demonstrated the macromolecular nature of this abnormal creatine kinase.
mesh_terms: D002384:Catalysis; D003402:Creatine Kinase / Q000097:blood* / Q000276:immunology; D005189:False Positive Reactions; D006801:Humans; D007158:Immunologic Techniques; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase