Elevated ALT is the first consideration for liver disease, but the exact type of liver disease needs to be further clarified. In some cases, the cause of liver disease is relatively easy to detect, such as viral infections and alcoholic liver injury, which can often be clarified by taking a medical history and performing routine tests. Other liver diseases are more difficult to diagnose, such as autoimmune liver disease and metabolic liver disease, and often require a liver puncture biopsy as well as special tests to confirm the diagnosis. With the wide use of antiviral drugs and hepatitis B vaccine, the elevation of liver transaminases caused by hepatitis B is on the decline, while other liver diseases, such as fatty liver caused by alcohol or metabolic factors, and autoimmune liver disease are on the rise. Etiology is also an important part of the diagnosis, as only by treating the cause of the disease can we truly maintain health in the long term.