Diagnostic efficiency of four lactate dehydrogenase isoenzyme-1 ratios in serum after myocardial infarction.
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.
Loughlin
J F
JF
Department of Clinical Biochemistry, University Hospital (University of Western Ontario), London, Canada.
Krijnen
P M
PM
Jablonsky
G
G
Leung
F Y
FY
Henderson
A R
AR
D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000201:enzymology; D012984:Software
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase