Clinical performance of the new cardiac markers troponin T and CK-MB on the Elecsys 2010. A multicentre evaluation.
Elecsys assays for the cardiac markers Troponin T (cTnT) and CK-MB have been evaluated in an international multicenter study on the random access analyzer Elecsys 2010 to characterize their clinical performance and their comparability with respective established routine methods. In method comparison studies of Elecsys Troponin T (TnT) with Enzymun-Test TnT, good correlations (r > or = 0.95) and a high degree of correspondence (slopes in 4 laboratories between 0.95 and 1.05) were found. The method comparison studies of Elecsys CK-MB with various CK-MB routine methods lead to good correlations but some systematic deviation in the slopes due to varying standardization. In a reference population of 350 persons upper reference limits (97.5th percentile) of 0.03 milligrams/l for Elecsys TnT and 3.1 milligrams/l for Elecsys CK-MB were found. In cardiosensitivity studies the equivalent diagnostic information of the new Elecsys assays to routine methods was confirmed in the early diagnosis of acute myocardial infarction (AMI), the detection of minor myocardial damages in patients with unstable angina pectoris (UAP) and in time course data monitoring of AMI and bypass surgery patients. The superior sensitivity of cTnT versus CK-MB has been established in a screening situation where in 29 patients with cardiac diseases only cTnT, but not CK-MB, was found pathologically increased; this was due either to the larger diagnostic window of cTnT in AMI or to the more sensitive recognition of minor myocardial damage. In the same study, the cardiospecificity of Elecsys TnT was found to be at least 99.5%. This has also been demonstrated in an earlier study for Enzymun-Test TnT. Further cardiospecificity testing, e.g. in renal failure patients, showed results equivalent to those of Enzymun-Test TnT. An extended clinical study involving 294 patients with chest pain, of whom 58 had a final diagnosis of AMI, revealed highly comparable sensitivity and specificity for the Elecsys assays and routine methods. Thus, the already recommended clinical cut-off values of 0.1 milligrams/l for cTnT and 5 milligrams/l for CK-MB are also valid for the Elecsys assays. The slightly improved sensitivity of Elecsys TnT in the lower range even allows the recognition of pathological increase at cTnT concentrations below 0.1 milligrams/l in special situations with sufficient additional clinical information. Summarizing, provide the two cardiac markers on the Elecsys 2010 at least equivalent or even superior diagnostic information in various clinical situations of cardiac disease compared with routine methods. The short turn-around time and reliable performance qualify the Elecsys assays as new methods of choice for routine and emergency use.
Klein
G
G
Boehringer Mannheim GmbH, Mannheim/Penzberg, Germany.
Kampmann
M
M
Baum
H
H
Rauscher
T
T
Vukovic
T
T
Hallermayer
K
K
Rehner
H
H
Müller-Bardorff
M
M
Katus
H A
HA
D000328:Adult; D000368:Aged; D001026:Coronary Artery Bypass; D003402:Creatine Kinase / Q000097:blood*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D007527:Isoenzymes; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000201:enzymology; D011183:Postoperative Complications / Q000175:diagnosis / Q000201:enzymology; D011237:Predictive Value of Tests; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014336:Troponin / Q000097:blood*; D020107:Troponin T
D007527:Isoenzymes; D014336:Troponin; D020107:Troponin T; D003402:Creatine Kinase