title: Macro-creatine kinase as an interference in CK isoenzyme determinations.
abstract: Creatine kinase (CK) isoenzyme determinations have been performed on a series of specimens containing macro-CK, an atypical isoenzyme variant seen in approximately 1% of patients. These specimens were obtained from 2 different patients. Isoenzyme determinations were made using four different methods: electrophoresis (Corning ACI), column chromatography (Dupont ACA), immunoinhibition (ESKACHEM), Smith Kline), and immunoprecipitation (Isomune-CK, Roche). In specimens containing macro-CK, electrophoresis showed no false-positive CK-MB determinations, and immunoprecipitation showed 1 in 8 false-positives, while column chromatography and immunoinhibition each showed 4 of 4 false positives. When utilizing these methods, the possibility of false-positive CK-MB determinations must be taken into consideration as a possible explanation for positive CK-MB results which do not agree with the clinical assessment of the patient.
mesh_terms: D002852:Chromatography, Ion Exchange; D003402:Creatine Kinase / Q000037:antagonists & inhibitors / Q000097:blood*; D004587:Electrophoresis, Agar Gel; D006358:Hot Temperature; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase