Abnormal liver enzyme levels. Evaluation in asymptomatic patients. Chronic elevation of serum aminotransferase levels, even in the absence of symptoms, often reflects chronic hepatitis or other significant underlying liver disease. Patients with persistently abnormal alkaline phosphatase levels may have extrahepatic biliary tract disease or a chronic cholestatic disorder. Physicians can discover unsuspected liver disease without undue risk, expense, or inconvenience to the patient by means of the following: a carefully taken history and thorough physical examination, appropriate timing of follow-up blood tests, and timely referral for percutaneous liver biopsy or endoscopic retrograde cholangiopancreatography. 