title: Immunoglobulin-associated creatine kinase masquerading as macro-creatine kinase type 2 in a statin user.
abstract: Macro-creatine kinase (CK) is a cause of falsely elevated CK. Macro-CK type 1 is immunoglobulin-associated CK; type 2 is polymeric mitochondrial-CK. An elderly asymptomatic lady had an elevated CK level after receiving statin therapy. Her CK gel electrophoresis analysis demonstrated coexisting macro-CK type 1 and type 2 patterns. Further analysis by immunofixation and mixing this patient's serum with CK control material revealed an IgG-associated macro-CK that mimicked the electrophoretic pattern of macro-CK type 2. This highly unusual discovery suggests the possibility of the misinterpretation of macro-CK type 1 as macro-CK type 2. Falsely elevated CK is still common despite modern laboratory instrumentation and should be investigated.
authors.affiliation: Department of Laboratory Medicine, National University Hospital, Singapore. lohtp@yahoo.com
authors.forename: Tze Ping
authors.initials: TP
authors.lastname: Loh
authors.forename: Yan Hoon
authors.initials: YH
authors.lastname: Ang
authors.forename: Siew Fong
authors.initials: SF
authors.lastname: Neo
authors.forename: Cecilia
authors.initials: C
authors.lastname: Yin
authors.forename: Moh Sim
authors.initials: MS
authors.lastname: Wong
authors.forename: Sai Mun
authors.initials: SM
authors.lastname: Leong
authors.forename: Sharon
authors.initials: S
authors.lastname: Saw
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Sethi
mesh_terms: D000368:Aged; D003402:Creatine Kinase / Q000097:blood*; D015180:Electrophoresis, Gel, Two-Dimensional; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D007074:Immunoglobulin G / Q000097:blood*
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007074:Immunoglobulin G; D003402:Creatine Kinase