Comparison of the effectiveness of four clinical chemical assays in classifying patients with chest pain.

Abstract

We compared the usefulness of four serum assays for classifying patients originally suspected of having an acute myocardial infarction. One of these is the long-used measurement of total creatine kinase (CK) activity. The other three are relatively new immunoassays: myoglobin by RIA, CK-BB by RIA, and CK-MB by immunoinhibition. When we evaluated test effectiveness with use of conventionally derived reference ranges, the results were misleading. However, by using receiver operating characteristic curves, we were able to effectively compare the four tests at all possible decision levels, rather than at only one. Multiple closely sequential serum specimens were obtained during the first four days after the onset of chest pain. Total CK, CK-MB, and CK-BB all behaved similarly, reaching peak diagnostic effectiveness at 18-20 h, when all three correctly classified 95% of the infarct patients, with a zero false-positive rate. However, total CK was more useful in identifying infarcts later in their courses than were the two CK isoenzyme tests. Myoglobin assay was most effective earlier in the course, at about 7 to 8 h. Our results indicate (a) that the tests for myoglobin and for CK or its isoenzymes are complementary and (b) that of the three CK tests, measurement of total CK activity provides the most information over the broadest segment of a patient's course.

Evaluating presence–absence models in ecology: the need to account for prevalence

“…1; Albert & Harris 1987;Walker, Cross & Harrison 1999). In these instances, several statistical methods have been developed to evaluate model performance (Robertson & Zweig 1981;Van Steirteghem et al . 1982;Robertson, Zweig & Van Steirteghem 1983;Zweig, Broste & Reinhart 1992;Zweig & Campbell 1993).…”

Including climate change in pest risk assessment: the peach fruit fly,Bactrocera zonata(Diptera: Tephritidae)

“…Models can be assessed with four measures of model accuracy: sensitivity, specificity, Cohen's kappa and the area under the curve (AUC) of receiver-operating characteristic (ROC) plots. The AUC of ROC was developed from signal detection theory (Kraemer, 1988) and have been adapted for several areas of medical diagnostics (Robertson & Zweig, 1981; Van Steirteghem et al ., 1982; Zweig & Robertson, 1982; Robertson et al ., 1983; Zweig et al ., 1992; Zweig & Campbell, 1993). Compared with other measures, such as Cohen's kappa (McPherson et al ., 2004) and TSS (true skill statistic) (Allouche et al ., 2006), AUC is largely unaffected and does not respond to changes, thus it is a more reliable.…”