title: Is determination of creatine kinase-2 after electrophoretic separation accurate?
abstract: Since 1991, the Ontario Laboratory Proficiency Testing Program has assessed the analytical performance of creatine kinase (CK; EC 2.7.3.2) isoenzyme-2, using fresh human serum supplemented with purified human CK isoenzymes. In Ontario, the 142 laboratories licensed to analyze CK-2 use a variety of methods: electrophoresis-based, immunoinhibition, and mass assays. During a 1992 survey, duplicate CK-2 samples with different total CK activities showed poorer precision when analyzed after electrophoretic separation than by any other method. A 1993 survey designed to validate these observations conclusively showed that electrophoresis-based assays are subject to a bias proportional to the total CK activity. These survey results were confirmed by studies with selected patients' specimens. We therefore conclude that electrophoresis-based assays may not warrant their reputation as the gold standard for CK isoenzyme measurement.
authors.affiliation: Laboratory Proficiency Testing Program, Toronto, Ontario, Canada.
authors.forename: A R
authors.initials: AR
authors.lastname: Henderson
authors.forename: J A
authors.initials: JA
authors.lastname: Stark
authors.forename: M J
authors.initials: MJ
authors.lastname: McQueen
authors.forename: R L
authors.initials: RL
authors.lastname: Patten
authors.forename: S
authors.initials: S
authors.lastname: Krishnan
authors.forename: D E
authors.initials: DE
authors.lastname: Wood
authors.forename: S
authors.initials: S
authors.lastname: Webb
mesh_terms: D003402:Creatine Kinase / Q000097:blood*; D004586:Electrophoresis; D006801:Humans; D007118:Immunoassay / Q000706:statistics & numerical data; D007124:Immunoenzyme Techniques / Q000706:statistics & numerical data; D007527:Isoenzymes; D011786:Quality Control; D012680:Sensitivity and Specificity
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase