Frequently, abnormal liver function is discovered during routine blood work and should be followed up on immediately. Many illnesses cause the liver to malfunction including, hepatitis, fatty liver disease, cirrhosis, liver cancer, and heart disease. Because some of these can be life threatening you should seek medical attention immediately. 

Other symptoms of liver disease can include:  weakness, fatigue, loss of appetite, jaundice (yellowing of the eyes and skin), dark urine, light colored stool, abdominal swelling and pain, nausea and vomiting, and itching.