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Diagnosis and Monitoring Hepatitis C Infection

Fall 1999

A note from The field of medicine is constantly evolving. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

Learning if you have been exposed to HEP C is not so difficult, finding out if you are infected, and if so, what is going on in your body as a result of the infection can be. Ultimately you will need a number of tests to give you this important information.

To learn whether or not you have been exposed to HEP C, start with a HEP C antibody test, also known as HEP C ELISA, which looks for antibodies that your immune system produces after you are exposed. In general most individuals that are exposed to HEP C will produce antibodies eventually, unless they are severely immunocompromised. The test can be tricky. False positives show up in about one out of every four cases. If your test is negative, and you know that you are at risk, follow it up with a more specific test called a qualitative HEP C PCR to make sure (see below).

Viral Load Testing (PCR)

If you get a positive antibody test it doesn't always mean you actually have HEP C infection. About 15% of people with the antibody are not chronically (long term) infected. If you are positive, however, you will want to get a qualitative HEP C PCR (viral load) test. This test is similar to an HIV viral load test and actually looks for the virus in your blood. The qualitative PCR won't tell you how many HEP C virus particles there are in your blood sample but it will tell you whether there are any present. Even if this test comes back negative and you are at high risk, your doctor may recommend that you repeat the test in a few months since levels of the virus fluctuate. The incubation period for HEP C varies from two weeks to six months. If the PCR is negative a second time, the antibody test may have been a false positive, or you may be one of those lucky 15% whose bodies clear the infection on their own.


Tests Used to Diagnose and Monitor HEP C
Test Name What it is Used For
Elisa (EIA)
Hepatitis C Antibody Test
A blood test that detects antibodies that the immune system produces in response to exposure to HEP C. Used to tell if a person has been exposed. Positive test results in a person with elevated liver emzymes and risk factors usually indicates infection.
Recombinant Immunoblot Assay (RIBA) A blood test used to confirm the antibody test. Should be considered for low risk individuals with a positive antibody test. May become less relevant with the advent of HCV RNA testing.
Quantitative HCV RNA Test Used to detect the presence of HEP C RNA in the blood to confirm HEP C infection in a person with a positive antibody test. Known as PCR or bDNA.
Qualitative HCV RNA Test A blood test used to detect the amount of virus in a person's blood. Can be used to guide therapy and may assess risk of progression.
Genotyping A blood test used to tell which strain of HEP C a person is infected with. Certain genotypes respond better to therapy.
Liver Function Tests A blood test used to moniter liver function. Detects presence of liver emzymes in the blood. Two of the most common are known as AST and ALT. High liver emzyme levels may indicate liver damage.
Liver Biopsy Thought of as the "gold standard" to determine the stage and cause of liver disease. A surgical procedure usually done in a hospital.

The second type of PCR test or viral load test is quantitative, which means it tells you how much virus is in a particular sample of blood. Most people with HEP C have viral loads anywhere between 100,000 and ten million, and sometimes higher. There's no comparison between HEP C viral loads and those for HIV. Whereas a viral load of one or two million is considered very high in HIV, the same result in HEP C isn't necessarily considered high. There is almost no information yet about how specific HEP C viral load levels relate to the likelihood of current or future liver damage. So, as with liver enzymes, don't make any decisions based solely on viral load results.

Monitoring Disease Progression

Once you are sure that you are chronically infected with HEP C, you will want to know what condition your liver is in so that you can make important treatment decisions. As your liver goes about its business, it secretes enzymes into your blood which are measured each time you get your blood work. If you're HEP C-positive, most doctors will simply monitor your liver enzymes (ALT, AST) every six months. It's a good idea to get a baseline reading, however your enzyme numbers can be affected by so many variants that they're only worthwhile for comparison purposes over time. If you're taking anti-HIV medications for example, or any medications for that matter, your liver enzymes may be on the high end as your liver works overtime to metabolize (break down) the medications. And if your liver is in really bad shape, your enzyme levels may be normal or low because your liver is too worn out to make the enzymes. Alcohol and street drugs can also significantly damage the liver, resulting in increased liver function tests. So, overall, monitoring liver enzymes isn't a useful indicator of liver damage, but can be used with other tests to tell you what state you liver is in.

Your doctor may also want to get a quantitative HEP C PCR (viral load) over time for comparison which tells you how much hepatitis C virus you have in your blood.

Liver Biopsy

You can monitor your symptoms, liver enzymes and HEP C viral load, but without having a liver biopsy, you really can't tell how your liver is doing. If you're feeling just fine, you're unlikely to jump at the chance to go through an invasive, uncomfortable, if not downright painful procedure. A liver biopsy is currently the most accurate way to measure the progression of liver damage. This is an outpatient procedure that just takes a few minutes while you're awake. A needle is inserted through your abdomen, just below your right ribs, into your liver, and a small tissue sample is taken out and examined under a microscope by a doctor called a pathologist. Because the sample is only from one part of the liver it can't tell you what's going on in other parts of your liver, but it is a useful diagnostic tool to measure the degree of inflammation, fibrosis and cirrhosis in that sample. It's particularly important and at present, necessary if you're considering treatment. Liver biopsy can be repeated to assess disease progression over time. As with any surgical procedure, preparation is required and there are risks involved. It is important to understand everything your doctor says to you about a biopsy before you undergo one.

Genotypic Tests

Of the three main HEP C genotypes (1, 2 and 3), genotype 1 is the most common in the United States, accounting for about 70% of US infections. It is also, unfortunately, the genotype least likely to respond to the treatments currently available. A genotype describes the basic genetic make-up of your particular strain of virus. Learning your genotype may give you some statistical information about how likely you are to benefit from treatment, but at this time it's still primarily a research tool.

The language used by many HEP C researchers is curious and inaccurate. When you look through the literature at studies and articles or attend research presentations, terms such as "cure," "eradication," and "PCR-negative" repeatedly come up. These words can be misleading and confusing. However, largely due to PLWAs' influence on the language of HIV and the many researchers and doctors who understand the importance of using language that reflects what's truly going on, the language of HEP C is slowly evolving. "PCR-negative" is now often replaced by "undetectable viral load"; "eradication" is most often used only when talking about that 15% or so of folks who spontaneously clear the virus from their systems after initial infection; and that loaded word "cure" appears less often now, when what is really meant is a sustained undetectable viral load.

James Learned is currently working with the Hepatitis-C Action and Advocacy Coalition (HAAC).

Managing Drug Side Effects

Community Research Initiative on AIDS (CRIA) is pleased to announce the publication of its newest educational brochure, "Managing Drug Side Effects". This brochure has been produced by CRIA to help people understand the different side effects that are commonly associated with the drugs prescribed for HIV disease and the ways to deal with them. Thanks to Agouron Pharmaceuticals, Bristol-Myers Squibb, Du Pont Pharmaceuticals, and Merck and Co., Inc. for unrestricted educational grants to fund this project. If you are an AIDS service provider and would like to receive free bulk copies of this brochure, or our brochure "Understanding Your Laboratory Results," please call CRIA at 212-924-3934, or write to us at CRIA, 230 West 38th Street, 17th Floor, New York, NY 10018.

A note from The field of medicine is constantly evolving. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

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This article was provided by AIDS Community Research Initiative of America. It is a part of the publication CRIA Update. Visit ACRIA's website to find out more about their activities, publications and services.
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