Low hydroxybutyrate dehydrogenase can be caused by the use of immunosuppressive drugs, malignant tumors undergoing chemotherapy, or congenital low hydroxybutyrate dehydrogenase. The normal value of hydroxybutyrate dehydrogenase is usually between 90 and 220 U. The measured value actually reflects the activity of the lactate dehydrogenase isoenzyme, so it is important for the diagnosis of myocardial ischemia, myocardial necrosis and liver disease. 1. Use of immunosuppressive drugs: immunosuppressive drugs such as cyclophosphamide may inhibit the catalytic oxidation function of a-hydroxybutyric acid dehydrogenase, thus making the value of hydroxybutyric acid dehydrogenase low. After the condition improves and after the doctor’s comprehensive evaluation, it can be considered to discontinue the use of the drug, and the index can be restored after discontinuing the use of the drug. 2. Malignant tumors in the chemotherapy period will lead to low hydroxybutyrate dehydrogenase, to be after chemotherapy for some time, the enzyme will gradually return to normal. Chemotherapeutic drugs include carboplatin, cytarabine and so on. 3. Congenital low hydroxybutyrate dehydrogenase is a hereditary mutation, which requires timely medical treatment. If you have low hydroxybutyrate dehydrogenase, please consult a doctor in time, and the specific diagnosis and treatment should be carried out under the guidance of a physician.