title: Comparison of cardiac troponin I and lactate dehydrogenase isoenzymes for the late diagnosis of myocardial injury.
abstract: Cardiac troponin I (cTnI) is a highly specific marker that is elevated in the blood for several days following myocardial infarction. The lactate dehydrogenase (LD) isoenzyme 1 to isoenzyme 2 ratio (LD1/LD2) is the established marker for the late diagnosis of myocardial infarction. In this study, the sensitivity of cardiac troponin I (cTnI) and LD1/LD2 were compared as late markers of myocardial injury over a 5-day period in 36 patients admitted with a diagnosis of myocardial infarction to the coronary care unit. Over this period, the sensitivity of cTnI was significantly greater than that of LD1/LD2 (P < .05). The concurrent elevation of both cardiac markers of the five day period range from 53.1% to 79.4%. However, this low concordance was largely due to an LD1/LD2 < 1 in the presence of an increased cTnI. The average discordance over the 5-day period was 29.5%. Because cardiac troponin I (cTnI) has greater sensitivity than lactate dehydrogenase isoenzymes for delayed diagnosis of myocardial injury and is a more cost-effective test, the authors recommend it as a test of choice in this setting.
authors.affiliation: Department of Pathology, University of Texas Southwestern Medical Center, Dallas 75235-9052, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Martins
authors.forename: D J
authors.initials: DJ
authors.lastname: Li
authors.forename: L B
authors.initials: LB
authors.lastname: Baskin
authors.forename: I
authors.initials: I
authors.lastname: Jialal
authors.forename: J H
authors.initials: JH
authors.lastname: Keffer
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D015200:Fluoroimmunoassay; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D019210:Troponin I; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase