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URL: http://www.hepatitis.va.gov/vahep?page=diag-tests-print&pp=pf | | | Laboratory Tests: Overview | | Once you've been diagnosed with hepatitis C, your VA doctor probably will order a number of tests to learn about your overall health, to decide whether drug therapy is appropriate, and to learn about your body's internal functioning (including how well your liver is working).
Some tests will be done very soon after you've been diagnosed with hepatitis C, while other tests will continue to be done on a regular basis. These tests will monitor your health and help you and your doctor decide when treatment is appropriate (or, if you've already begun treatment, whether it's working).
In the following sections, you can learn about the tests, why your doctor may have ordered them, and what the results mean. Note: Normal values for laboratory tests can vary from one lab to another. Check with your doctor on the normal range for your lab tests. |
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| Tests of the Liver | | If you have hepatitis C, most likely, your doctor will check blood tests of your liver. There's a handful of liver tests and it is helpful to know what each of them means. Here, we explain common liver blood tests and how to understand your results.
| Liver Function Tests (LFTs) | | | | | The phrase "liver function tests" or "LFTs" is commonly used by patients and physicians. Many patients and physicians use the term to describe the AST and ALT. However, this is not correct--the AST and ALT do not measure the function of the liver.
The true function of the liver is actually best measured by the PT, INR and albumin. Therefore, if you are getting a PT, INR or albumin, these tests can determine how the liver is "functioning."
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| AST (SGOT) | | | | | AST, or aspartate aminotransferase, is 1 of the 2 "liver enzymes." It is also known as serum glutamic-oxaloacetic transaminase, or SGOT. AST is a protein made by liver cells. When liver cells are damaged, AST leaks out into the bloodstream and the level of AST in the blood becomes higher than normal. AST is different from ALT because AST is found in parts of the body other than the liver--including the heart, kidneys, muscles, and brain. When cells in any of those parts of the body are damaged, AST can be elevated.
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| Explanation of test results: | | A high AST level often means there is some liver damage, but it is not necessarily caused by hepatitis C. A high AST with a normal ALT may mean that the AST is coming from a different part of the body. It is important to realize that the AST level in most patients with hepatitis C goes up and down. The exact AST level does not tell you how much liver damage there is, or whether the liver is getting better or worse, and small changes should be expected. However, for patients receiving treatment for hepatitis C, it is helpful to see if the AST level goes down.
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| Other things to know: | | - The AST level is not as helpful as the ALT level for checking the liver.
- Many patients with hepatitis C will have a normal AST level.
- Patients can have very severe liver disease or cirrhosis and still have a normal AST level.
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| Tests of Hepatitis C | | If you have hepatitis C virus, you are likely to have a doctor recommend a few different hepatitis C blood tests, not just one. It is helpful to understand what each of these blood tests mean. Here we explain the common blood tests of hepatitis C and the meaning of test results. | Hepatitis C Antibody (HCV Ab, anti-HCV) | | | | | This is the first test for determining whether you have been infected with hepatitis C. The results will come back as either positive or negative.
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| Explanation of test results: | | If this test result is positive, it means your body was exposed to the hepatitis C virus and made antibodies (for more information, see "Antibody" section under Associated Lab Tests). However, it does not tell you whether you are still infected with hepatitis C. If the antibody test result is positive, you should be tested for hepatitis C RNA (see "Hepatitis C RNA"), which determines whether you are chronically infected. The lab might perform this RNA test automatically if your hepatitis C antibody test is positive or your doctor might need to order the Hepatitis C RNA test separately.
If the antibody test result is negative, it means you have not been infected with the hepatitis C virus, and further testing for hepatitis C usually is not needed.
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| Other things to know: | | - After a successful course of treatment for hepatitis C, the hepatitis C antibody remains detectable, but the hepatitis C RNA will be undetectable.
- Any patient with a positive test result for the hepatitis C antibody should have additional tests to determine whether or not the virus is still active.
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| Hepatitis C Genotype | | | | | The hepatitis C genotype is a type or "strain" of hepatitis C virus. There are 6 genotypes of hepatitis C around the world. In the United States, 3 genotypes are common: - Genotype 1
- Genotype 2
- Genotype 3
These can be further specified as: - Genotype 1a or 1b
- Genotype 2a or 2b
- Genotype 3a or 3b
The genotype of hepatitis C does not change over time. It needs to be tested only once.
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| Associated Lab Tests | | Patients with hepatitis C often have a wide variety of blood tests requested by their doctor. In addition to tests of hepatits C and tests of the liver, you may have tests of your kidney, blood counts, thyroid and others. It is especially important to understand these tests if you are taking hepatitis C treatments. Here we explain the meaning of some of the most common blood tests you may want to understand. | Hepatitis B Virus Testing | | |
| Antibody | | | | | Antibodies are part of the immune system's response to infection. Once an infection has taken place, the body makes antibodies, which become detectable in the bloodstream. Different antibodies fight different infections.
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| Explanation of test results: | | If you have a positive test result for a specific antibody, it means that your body has had an immune response to that specific infection. It does not necessarily mean you are still infected--it does mean that you were infected at some point in the past.
The hepatitis C antibody is explained under Hepatitis C tests.
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| Resources | | - American Liver Foundation
(http://www.liverfoundation.org/) A national nonprofit organization dedicated to the prevention, treatment, and cure of hepatitis and other liver diseases through research, education, and advocacy. Web site features a database directory of hepatitis clinical trials, lay-oriented facts sheets, and links to additional resources.
- Centers for Disease Control and Prevention: Viral Hepatitis
(http://www.cdc.gov/ncidod/diseases/hepatitis/index.htm) Information on all types of viral hepatitis from the CDC's National Center for Infectious Diseases. Site features related CDC guidelines and recommendations as well as training materials, slide sets, fact sheets, and key CDC hepatitis documents.
- NATAP: Hepatitis
(http://www.natap.org/hepc.htm) Recognizing that coinfection with viral hepatitis among people with HIV is a growing problem, the National AIDS Treatment Advocacy Project (NATAP) has developed an extensive amount of information on hepatitis, both in the context of HIV coinfection and as a separate illness. NATAP provides coverage of key conferences, maintains a selection of hepatitis articles, and features an ask-the-expert forum on hepatitis C.
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Reviewed/Updated Date: February 2, 2007 |
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