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.

What do high (elevated) liver tests (AST and ALT) mean?

AST (SGOT) and ALT (SGPT) are reasonably sensitive indicators of liver damage or injury from different types of diseases or conditions, and collectively they are termed liver tests or liver blood tests. However, it must be emphasized that higher-than-normal levels of these liver enzymes should not be automatically equated with liver disease. They may mean liver problems or they may not. For example, elevations of these enzymes can occur with muscle damage. The interpretation of elevated AST and ALT results depends upon the entire clinical evaluation of an individual, and so it is best done by physicians experienced in evaluating liver disease and muscle disease.

Moreover, the precise levels of these liver enzyme tests do not correlate well with the extent of liver problems or the prognosis (outlook). Thus, the exact levels of AST (SGOT) and ALT (SGPT) cannot be used to determine the degree of liver disease or predict the future prognosis for liver function. For example, individuals with acute viral hepatitis A may develop very high AST and ALT levels (sometimes in the thousands of units/liter range), but most people with acute viral hepatitis A recover fully without residual liver disease. Conversely, people with chronic hepatitis C infection typically have only a little elevation in their AST and ALT levels while having substantial liver injury and even advanced scarring of the liver (cirrhosis) from ongoing minor inflammation of the liver.

Do AST and ALT test results indicate liver function?

It is important to clarify that ALT and AST levels do not reflect the function of the liver, even though in the medical community and in medical publications they commonly, and incorrectly, are referred to as liver function tests. Even in conditions when AST and ALT are very elevated, the liver still may function properly. Consequently, if you have "...elevated liver enzymes" or a high or abnormal liver test, you need to ask your physician exactly what all of the tests indicate. Continue Reading

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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