Liver Blood Tests

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    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.

Liver Disease Symptoms

The liver has multiple functions. It makes many of the chemicals required by the body to function normally, it breaks down and detoxifies substances in the body, and it also acts as a storage unit. When the liver is damaged from disease, medication, alcohol, or other factors., a person may have symptoms of liver disease such as

  • nausea and vomiting
  • jaundice (yellowing of the skin),
  • fatigue,
  • weakness,
  • shortness of breath,
  • excessive bruising or bleeding, and
  • leg swelling.

What are the basic functions of the liver?

The liver is located in the right upper portion of the abdominal cavity just beneath the rib cage. The liver has many functions that are vital to life. Briefly, some of the important functions of the human liver are:

  • Detoxification of blood
  • Production of important clotting factors, albumin, and many other important proteins
  • Metabolizing (processing) medications and nutrients
  • Processing of waste products of hemoglobin and other cells
  • Storing of vitamins, fat, cholesterol, and bile
  • Production of glucose (gluconeogenesis or glucose synthesis/release during starvation)

What are common liver blood function tests?

Liver blood tests are some of the most commonly performed blood tests. These tests can be used to assess liver functions or liver injury. An initial step in detecting liver damage is a simple blood test to determine the level of certain liver enzymes (proteins) in the blood. Under normal circumstances, these enzymes mostly reside within the cells of the liver. But when the liver is injured for any reason, these enzymes are spilled into the blood stream. Enzymes are proteins that are present throughout the body, each with a unique function. Enzymes help to speed up (catalyze) routine and vital chemical reactions in the body.

Among the most sensitive and widely used liver enzymes are the aminotransferases. They include aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). These enzymes are normally predominantly contained within liver cells and to a lesser degree in the muscle cells. If the liver is injured or damaged, the liver cells spill these enzymes into the blood, raising the AST and ALT enzyme blood levels and signaling liver disease.

Other blood tests pertaining to the liver are measurements of some of the other enzymes found the liver. In addition to AST and ALT, alkaline phosphatase, 5' nucleotidase, and gamma-glutamyl transpeptidase (GGT) are a few of the other enzymes located in the liver. The focus of this article is mainly on the most common liver enzymes, AST and ALT.

Reviewed on 4/20/2016
References
REFERENCES:

Brailita, D. M. "Amebic Hepatic Abscesses Workup." Medscape. Udpated Apr 15, 2015.
<http://emedicine.medscape.com/article/183920-workup>

Sears, D. MD. "Fatty Liver." Medscape. Updated Nov 30, 2015.
<http://emedicine.medscape.com/article/175472-overview>

Sood, G. "Acute Liver failure workup." Medscape. Updated Feb 04, 2016.
<http://emedicine.medscape.com/article/177354-workup>

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