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    Liver Function Tests

    Liver Function Tests

    Exam Overview

    Some blood tests are used to determine whether your liver is damaged or inflamed. Although these tests help your doctor evaluate how well your liver is working, they cannot tell if you have hepatitis C .

    Tests that assess liver function

    Your doctor may do tests to measure certain chemicals produced by the liver. These tests can help your doctor check how well your liver is working.

    Tests may measure:

    Tests that check for inflammation of the liver (liver enzyme studies)

    Your liver may be damaged if you have increased levels of:

    An increased level of alkaline phosphatase (AP) may indicate blockage of bile ducts.

    Why It Is Done

    Liver tests are done when a medical history or physical exam suggests that something may be wrong with your liver.

    These tests can also help diagnose long-term (chronic) infection. Hepatitis C infection is considered chronic when liver enzymes remain elevated for longer than 6 months.

    If you are being treated with antiviral therapy, you may have liver tests from time to time to see whether treatment is working.

    Results

    Findings of liver function tests may include the following:

    Normal

    All levels are within the normal range.

    Abnormal

    One or more levels are outside the normal range. Abnormal liver function tests may indicate that your liver is inflamed or is not working normally. This can be a sign that you have a viral infection.

    What To Think About

    Elevated liver enzymes can be caused by many things other than hepatitis C, such as obesity, hepatitis B , autoimmune hepatitis, certain medicines, or long-term alcohol use. So you will need other tests (such as a hepatitis C antibody blood test or a liver biopsy) to confirm a diagnosis of hepatitis C.

    People with chronic hepatitis C have abnormal liver enzyme levels most of the time. But the levels can fluctuate between normal and abnormal throughout the course of the disease.

    Liver tests can be used to help you and your doctor develop a treatment plan. Signs that you might need treatment include:

    • Liver enzyme levels that remain above normal for longer than 6 months, which is evidence of chronic infection.
    • Detectable levels of hepatitis C virus in your blood (positive hepatitis C RNA test). This is a sign of an active infection.
    • Evidence of serious liver damage. This is detected with a liver biopsy .

    Complete the medical test information form (PDF) (What is a PDF document?) to help you prepare for this test.

    Credits

    By Healthwise Staff
    Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
    Specialist Medical Reviewer W. Thomas London, MD - Hepatology
    Last Revised June 27, 2013

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