The reasons for the clinical elevation of hydroxybutyrate dehydrogenase may be related to acute myocardial infarction or pernicious anemia. 1. Acute myocardial infarction: High levels of hydroxybutyrate dehydrogenase in acute myocardial infarction occur due to rupture of coronary atherosclerotic plaques and formation of blood clots, which leads to myocardial necrosis. When the level of hydroxybutyrate dehydrogenase is high, it is also necessary to determine whether there is myocarditis or muscular dystrophy, which is considered to be related to myocardial damage. 2. Pernicious anemia: Pernicious anemia is due to atrophy of the gastric mucosa, resulting in the absorption of vitamin B₁₂, the cause of which is not clear, and high hydroxybutyrate dehydrogenase levels can occur. It is recommended to consult the cardiovascular medicine department of regular hospitals firstly when high level of hydroxybutyrate dehydrogenase is found, so as to clarify the cause of the disease and diagnose and treat the disease in a timely manner.