Re-evaluation of the diagnostic utility of serum total creatine kinase and creatine kinase-2 in myocardial infarction.
The diagnostic utility of total creatine kinase activity (I), creatine kinase-2 isoenzyme activity (II), and II as a percentage of I, was examined by receiver-operating characteristic curve and likelihood ratio (LR) analyses in 310 persons admitted to the Coronary Care Unit (151 proven cases of myocardial infarction and 159 non-myocardial infarction controls), from whom blood was sampled at 6-h intervals for 48 h after the onset of chest pain. I was ineffective either as a "rule-in" or as a "rule-out" test within the first 6 h of the onset of chest pain; thereafter, it was an effective test. II was the most effective test during the entire 48-h period. III was more effective than I in the first 24-h period, but was less effective than I during the next 24-h period. The decision threshold for high test sensitivities varies with time over the entire 48-h period, but remains constant for high test specificities. It is essential to tabulate the LR(+) and LR(-) values for both test sensitivity and specificity at constant values to determine the utility of each test at each time interval for respectively ruling out or ruling in a diagnosis of myocardial infarction.
Leung
F Y
FY
Department of Clinical Biochemistry, University Hospital (University of Western Ontario), London, Canada.
Galbraith
L V
LV
Jablonsky
G
G
Henderson
A R
AR
D003402:Creatine Kinase / Q000097:blood*; D003951:Diagnostic Errors; D006801:Humans; D007527:Isoenzymes; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D012372:ROC Curve; D013997:Time Factors
D007527:Isoenzymes; D003402:Creatine Kinase