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Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• Liver facts
• Liver overview
• How large is the liver?
• Where is the liver located (liver anatomy)?
• What is the function of the liver?
• What special features enable the liver to do so much?
• What diseases affect the liver?
• How do liver diseases cause symptoms?
• What about blood tests for the diagnosis of liver disease?
• Why does the doctor examine the liver?
• What is a liver biopsy?
• What else is important about the liver?
• Find a local Doctor in your town
• Liver Index

Damage to the liver often gives rise to telltale abnormalities in certain blood tests (suggesting liver disease), the so-called liver blood tests (for example, ALT, AST, and alkaline phosphatase enzymes). As a matter of convenience, the liver blood tests often are collectively referred to as liver function tests. But, abnormalities in only some of them (i.e., elevated bilirubin, low albumin, and prolonged prothrombin time) actually reflect, at least in part, abnormal function of the liver. And, it turns out that abnormalities of the other liver blood tests may reflect the actual injury to the liver. For example, viral hepatitis can cause the ALT or AST enzymes in injured liver cells to spill into the blood stream and increase their level in the blood.

Sometimes, the pattern of liver blood test abnormalities provides a clue as to the type of liver disease. For example, an AST to ALT ratio greater than two (as long as both are less than nine times normal) suggests alcoholic hepatitis or cirrhosis of any type.

Other blood tests are more specific for the diagnosis of particular liver diseases. For example, there are serological tests for most of the different types of viral hepatitis and immunological tests for primary biliary cirrhosis (antimitochondrial antibodies) or chronic autoimmune hepatitis (smooth muscle antibody). Additionally, there are special tests for hemochromatosis (iron-related tests), Wilson's disease (copper-related tests), and liver cancer (tumor markers).