The normal value of ALT is generally 0-40U/L, but the results may vary with different reagents and instruments. Therefore, when the value of ALT reaches 45U/L, it may also fall within the normal range. Even a mild elevation of ALT may not necessarily be caused by a disease. Drinking alcohol, eating high-fat foods, overexertion, staying up late at night, strenuous exercise, or taking certain medications may cause a mild elevation of ALT. After these triggers are removed, ALT will return to normal and does not require clinical treatment. Mildly elevated ALT may also be an early manifestation of certain liver diseases, as well as infections, heart and skeletal muscle diseases, etc. Therefore, clinical symptoms and relevant tests are needed to determine the cause and the need for treatment. However, attention should be paid to regular observation of changes in transaminase values and whether there is persistent elevation.