Hepatitis C is a sneaky virus. About 80% of infected people don't have any symptoms of the virus, and their liver shows only a little damage. Many of these people are diagnosed with hepatitis C after showing abnormal liver enzymes on routine blood tests. Other people -- about 5% to 20% -- develop cirrhosis after having the hepatitis C infection for 20 or 30 years. This is when the normal functioning liver is replaced by scar tissue. A smaller number of people develop liver cancer after infection...
Frank Anania, MD, associate professor of medicine and director of hepatology at Emory University School of Medicine in Atlanta.
Brian L. Pearlman, MD, medical director of the center for hepatitis C at the Atlanta Medical Center, Atlanta; and associate professor, Medical College of Georgia in Augusta.
What Is HCV Viral Load?
Dr. Pearlman: Viral load is [the number of] viral particles floating in the blood. These are copies of the genetic material of the virus circulating through the body.
Dr. Anania: Viral load is based on technology that lets us measure extremely small quantities of hepatitis C virus RNA, the building block of the virus.
Can I Be Positive for Hepatitis C if I Don't Have any Measurable Viral Load?
Dr. Pearlman: Being "hepatitis C positive" means you have anti-HCV antibodies in your blood. Having HCV antibodies just means you've been exposed to the hepatitis C virus. You can certainly be antibody positive and not have any measurable viral load. One lucky thing this might mean is that you are one of the nearly 20% of people who naturally clear the virus from their bodies. The other possibility is that the virus, during the time blood is drawn, was only temporarily undetectable. HCV viral load in the blood goes up and down, and the test might have caught it on a downswing. So before we tell someone they are negative, we ask them to have the test repeated.
Dr. Anania: After hepatitis C treatment, people still have antibodies to HCV. But if they have no detectable HCV viral load, that indicates recovery from infection -- that is, response to treatment and sustained remission. Over a period of time, if a later viral load test comes back undetectable, that patient is in remission.
What Is a High Viral Load and Low Viral Load?
Dr. Pearlman: Anything over 800,000 IU/mL is usually considered high. Anything under that is low viral load … Those with low viral load have a better chance of responding to treatment.
Am I Getting Sicker if My Viral Load Is Rising?
Dr. Anania: Not necessarily. With HCV, viral burden in hepatitis C does not necessarily predict the natural history of clinical disease. And therefore, patients need to understand that we use that measurement to help us guide therapy and response to therapy. We use it in conjunction with other types of laboratory data -- liver enzymes, liver biopsies sometimes, and viral genotype. Taken all together, these tests give us a snapshot of what is going on. But viral load numbers themselves do not predict disease.
Dr. Pearlman: Unlike HIV, HCV viral copies do not directly affect a patient's prognosis and how fast disease is progressing in the liver. Remember, we are measuring blood levels, not what is happening in liver cells. HIV viral load does have a lot to do with quicker progression to AIDS. But HCV viral load does not tell you how fast hepatitis is progressing.