Levinson S S, Hobbs G A
Department of Pathology, University of Louisville, KY.
Ann Clin Lab Sci. 1994 Jul-Aug;24(4):364-70.
Isoenzyme profiles of lactate dehydrogenase (percent LD-1 of total LD, LD-1/LD-2 ratio, and absolute LD-1) have all been studied as late markers for myocardial infarction. It is known, however, that elevations of LD-5 frequently occur in this period as a result of liver congestion. Elevations of LD-5 may also occur as a result of complicating conditions. Such elevations could result in a reduced percent LD-1 of total LD, giving rise to false negatives. Receiver operating characteristic (ROC) curves were constructed for LD-1, LD-1/LD-2 and percent LD-1 of total LD from 285 specimens (124 patients) with suspected myocardial infarction. There was little difference in overall diagnostic power among the three assays. Using cutoffs determined from the ROC curves, 6 patients (18 specimens) were evaluated who appeared to be in the late period or who exhibited complicating conditions which could increase LD-5. In 14/18 specimens, increases in LD-5 resulted in false negatives by percent LD-1 of total LD. Only 5/18 specimens were false negatives by LD-1 or LD-1/LD-2. It is concluded that the percent LD-1 of total LD was affected by an increase in LD-5, and caution is recommended when using it.
乳酸脱氢酶的同工酶谱（总乳酸脱氢酶中LD-1的百分比、LD-1/LD-2比值及LD-1的绝对值）均已作为心肌梗死的晚期标志物进行研究。然而，众所周知，在此期间由于肝淤血，LD-5经常升高。LD-5升高也可能是由于并发疾病导致。这种升高可能会使总乳酸脱氢酶中LD-1的百分比降低，从而产生假阴性结果。针对285份疑似心肌梗死标本（124例患者）构建了LD-1、LD-1/LD-2及总乳酸脱氢酶中LD-1百分比的受试者工作特征（ROC）曲线。这三种检测方法的总体诊断能力差异不大。使用根据ROC曲线确定的临界值，对6例似乎处于晚期或表现出可能增加LD-5的并发疾病的患者（18份标本）进行了评估。在18份标本中的14份中，LD-5升高导致总乳酸脱氢酶中LD-1百分比出现假阴性。只有18份标本中的5份通过LD-1或LD-1/LD-2出现假阴性。得出的结论是，总乳酸脱氢酶中LD-1百分比受LD-5升高的影响，使用时建议谨慎。
