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Causes of elevated lactate dehydrogenase 1 in blood
Medical expert of the article
Last reviewed: 04.07.2025
Determination of LDH 1 activity is used in clinical practice mainly for the diagnosis of myocardial infarction.
In patients with myocardial infarction, the activity of LDH 1 and partly LDH 2 in the blood serum increases sharply. The onset of the increase in LDH 1 activity coincides with that for total lactate dehydrogenase, but its duration for LDH 1 is longer - 10-12 days.
In angina pectoris, LDH1 activity does not change, therefore, with unclear clinical symptoms and normal overall LDH activity, an increase in LDH1 activity indicates small necrotic foci in the myocardium.
In liver diseases, the activity of LDH 5 and LDH 4 increases and the activity of LDH 1 and LDH 2 decreases.
In patients with progressive muscular dystrophy (myopathy), the activity of the isoenzymes LDH 1, LDH 2, LDH 3 increases in the blood, while LDH 4 and LDH 5 decreases. The degree of decrease in the activity of LDH 4 and LDH 5 in myopathy correlates with the severity of the disease.
In patients with acute leukemia, a distinct increase in the activity of the isoenzymes LDH 2 and LDH 3 is observed. In tumor diseases, the ratio LDH 5 /LDH 1 always exceeds 1. Tumor tissues are distinguished by significant activity of the isoenzymes LDH 3, LDH 4, LDH 5.
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