Measurement of creatine kinase isoforms by agarose gel electrophoresis in the diagnosis of myocardial infarction

Shu-Chu Shiesh, Wen Kao Ting, Tjin Shing Jap

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Abstract

To evaluate a method to quantitate the isoforms of serum creatine kinase isoenzyme MM (CK-MM) by agarose gel electrophoresis, sera of normal subjects (n = 74) and patients with acute myocardial infarction (n = 21) and other diseases (n = 67) were studied. The within-assay imprecision (CV) for CK-MM1, -MM2, and -MM3 was 1.9%, 0.8%, and 2.2% at the activity of 79, 105, and 64 U/L (30 °C, CK-NAC), respectively; while the assay-to-assay imprecision was 4.8%, 3.2%, and 3.9%, respectively. The method could detect 5 U/L or more of any CK-MM isoform and was linear with respect to CK activity at values < 1100 U/L. Sera from healthy subjects (n = 74) contained mainly CK-MM1 ({IF} = 48.5%), with lesser amounts of CK-MM2 ({IF} = 30.6%) and CK-MM3 ({if} = 20.8%). The central 95-percentile reference range for the ratio of MM3/MM1 was 0.12-1.34 with {if} = 0.49. The sensitivity of CK-MM3/MM1 ratio > 1.3 in the diagnosis of acute myocardial infarction employing the first available sample was 90% at a specificity of 91%, compared with a sensitivity of 81% and specificity of 87% for the conventional CK-MB assay. At CK-MM3/MM1 ratio of 1.6 or more, the specificity increased to 96% while sensitivity remained unchanged at 90%. This procedure for the quantitation of serum CK-MM isoforms is convenient, practical and suitable for inclusion in the routine panel of cardiac tests.

Original languageEnglish
Pages (from-to)293-301
Number of pages9
JournalClinical Biochemistry
Volume25
Issue number4
DOIs
Publication statusPublished - 1992 Jan 1

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All Science Journal Classification (ASJC) codes

  • Clinical Biochemistry

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