Serum lactate dehydrogenase catalyzes the formation of lactic acid from pyruvate in the body and is found in a wide range of tissues and organs in the body to help diagnose disease. Serum lactate dehydrogenase is a glycolytic enzyme found in a variety of tissues, including cardiac muscle, skeletal muscle, and kidneys, and more abundantly in liver, spleen, and tumors. Serum lactate dehydrogenase catalyzes the direct reductive oxidation of pyruvate and lactate, and is an important enzyme involved in the processes of anabolic glycolysis and gluconeogenesis. Clinically, its level can be tested. When it is high, it can be seen in diseases such as myocardial infarction, acute hepatitis, cirrhosis, malignant lymphoma, lung cancer, colon cancer, pulmonary embolism, and shock, etc. Its sensitivity is high, but its specificity is poor. When there is high serum lactate dehydrogenase, it is recommended to consult a doctor in time to clarify the diagnosis and standardize the treatment.