EARLY DIAGNOSIS OF ACUTE MYOCARDIAL-INFARCTION WITH USE OF A RAPID IMMUNOCHEMICAL ASSAY OF CREATINE-KINASE MB ISOENZYME

In 195 patients presenting with chest pain and referred acutely for ca rdiological assessment, blood was taken immediately for assay of creat ine kinase (CK; EC 2.7.3.2) MB isoenzyme by an immunochemical method a nd results [mass units of enzyme per liter of plasma (mug/L)] were obt ained within 30 min of sampling. Diagnosis of acute myocardial infarct ion in the patients was made independently, based on electrocardiogram s and conventional cardiac enzyme profiles. The administration of any thrombolytic therapy in response to the CK-MB concentration result was also noted, allowing assessment of the assay's potential influence on patient management in addition to the diagnostic efficiency evaluatio n. The study demonstrated that, when blood samples were collected on a dmission to hospital and the decision level suggested by the manufactu rers was utilized, the assay had an immediate sensitivity of 52% and a specificity of 97%. Of the 81 patients who were shown by conventional means to have had acute myocardial infarction, 8 (10%) had equivocal electrocardiograms but positive CK-MB concentration results. In four o f these patients (5%), thrombolytic therapy was given on the basis of the clinical features and a positive CK-MB concentration result alone.