Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.
Your health care practitioner will interview you about your illness. You will be
asked about your symptoms and about any exposures to hepatitis viruses.
If your doctor determines that you may be at risk for contracting hepatitis,
you will have blood drawn. The laboratory will be able to determine whether you
have acquired HCV and certain other hepatitis viruses.
Several tests are available for diagnosis, but the most widely used test
works by detecting antibodies to HCV. Antibodies are substances made by your
body's immune system to defend against a specific infection. It takes time for
antibodies to be produced, so the test may be falsely negative if it was
performed too soon (less than 4 to 10 weeks) after exposure to the virus.
Falsely positive tests may also occur, although the newer tests make this less
Patients with a positive antibody result should also be tested using a
'PCR' assay. The PCR measures the amount of virus in the blood, known as the
'viral load' or 'viral titer'. A positive viral load indicates active infection
and the test may be positive as early as 2 weeks after infection. A negative
viral load may mean that the infection has resolved, or it may mean that the
infection is active in the liver but not shedding virus into the blood stream at
the time the test was done.
In patients with positive antibodies, tests are also available to identify
which of the 6 common genotypes of the virus is causing the infection. This can
help determine the best treatment plan. In the United States, genotype 1 is the
The laboratory will also do several tests to determine how well your liver is
Other tests will probably be done to check the effects of the infection on
other body systems, such as the kidneys.
If the affected individual has had a large amount of vomiting or have not been able to take in
liquids, their blood electrolytes will be checked to see if they are in balance.
Liver biopsy is the ultimate test to determine whether the virus is causing
liver damage. It is not necessary for diagnosis, but provides useful information
about the stage of disease (the amount of liver damage that has already
occurred), and helps to decide whether treatment is needed.