title: Diagnostic efficiency of four lactate dehydrogenase isoenzyme-1 ratios in serum after myocardial infarction.
abstract: We compared the diagnostic efficacy of the ratios LD-1/LD-2, LD-1/LD-3, LD-1/LD-4, and LD-1/LD-5 in 69 documented cases of myocardial infarction. We used 149 patients with congestive heart failure and 67 patients with nonmyocardial infarct as controls. We used a computer program to produce receiver-operating characteristic curves, decision threshold plots, and likelihood ratios for these LD ratios at 6-h intervals up to 108 h after the onset of chest pain or hospital admission. All ratios in the myocardial infarction cases peaked around 36 h after the onset of chest pain, while those for the nonmyocardial and congestive cardiac failure cases did not change over the 108-h period. In all patients with infarctions, LD-1/LD-4 and LD-1/LD-5 increased by 1.7 times (when LD-1 was less than 40%) and 3.4 times (when LD-1 was greater than 40%), respectively, over control values. Optimum decision threshold values were obtained at 13-24 h (LD-1/LD-5), 31-36 h (LD-1/LD-4 and LD-1/LD-3), and 55-60 h (LD-1/LD-2) after onset of symptoms. The highest likelihood ratio was obtained with the LD-1/LD-4 ratio; therefore, we suggest that this is a better diagnostic test for myocardial infarction than LD-1/LD-2.
authors.affiliation: Department of Clinical Biochemistry, University Hospital (University of Western Ontario), London, Canada.
authors.forename: J F
authors.initials: JF
authors.lastname: Loughlin
authors.forename: P M
authors.initials: PM
authors.lastname: Krijnen
authors.forename: G
authors.initials: G
authors.lastname: Jablonsky
authors.forename: F Y
authors.initials: FY
authors.lastname: Leung
authors.forename: A R
authors.initials: AR
authors.lastname: Henderson
mesh_terms: D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000201:enzymology; D012984:Software
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase