GPT refers to alanine aminotransferase, also known as glutamate aminotransferase, which is abbreviated as ALT. Although the Chinese name and the English abbreviation are different, they represent the same clinical significance. Many organ cells contain alanine aminotransferase, but the activity of alanine aminotransferase in liver cells is much higher than that of other organ cells. It is known that alanine aminotransferase is mainly found in the cytoplasm of hepatocytes, and when hepatocytes are damaged, alanine aminotransferase in the cytoplasm is released into the blood, resulting in an increase in peripheral blood alanine aminotransferase values. Therefore, measurement of alanine aminotransferase is very important in assessing the extent of liver damage and can be used as a sensitive indicator of liver damage. There are many clinical causes of elevated alanine aminotransferase, such as disease, surgery, anesthesia, strenuous exercise, early pregnancy, use of certain medications, alcohol consumption, and prolonged sleepless nights. Therefore, attention should also be paid to identification to avoid missed diagnosis and misdiagnosis.