The following information comes from The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), a part of the National Institutes of Health (NIH) and the U.S. Department of Health and Human Services. To ensure that you’re viewing the most up-to-date information, we recommend visiting the chronic hepatitis c entry at the NIDDK website.

On this page:

  • Risk Factors and Transmission
  • Clinical Symptoms and Signs
  • Serologic Tests
  • Liver Biopsy
  • Noninvasive Tests
  • Diagnosis
  • Treatment
  • Hope through Research
  • For More Information

The hepatitis C virus (HCV) is one of the most important causes of chronic liver disease in the United States. It accounts for about 15 percent of acute viral hepatitis, 60 to 70 percent of chronic hepatitis, and up to 50 percent of cirrhosis, end-stage liver disease, and liver cancer.

Of the U.S. population, 1.6 percent, or an estimated 4.1 million Americans, have antibody to HCV (anti-HCV), indicating ongoing or previous infection with the virus. Hepatitis C causes an estimated 10,000 to 12,000 deaths annually in the United States.

A distinct and major characteristic of hepatitis C is its tendency to cause chronic liver disease in which the liver injury persists for a prolonged period if not for life. About 75 percent of patients with acute hepatitis C ultimately develop chronic infection.

Chronic hepatitis C varies greatly in its course and outcome. At one end of the spectrum are infected persons who have no signs or symptoms of liver disease and have completely normal levels of serum enzymes, the usual blood test results that indicate liver disease. Liver biopsy usually shows some degree of injury to the liver, but the extent is usually mild, and the overall prognosis may be good. At the other end of the spectrum are patients with severe hepatitis C who have symptoms, high levels of the virus (HCV RNA) in serum, and elevated serum enzymes, and who ultimately develop cirrhosis and end-stage liver disease. In the middle of the spectrum are many patients who have few or no symptoms, mild to moderate elevations in liver enzymes, and an uncertain prognosis.

Chronic hepatitis C can cause cirrhosis, liver failure, and liver cancer. Researchers estimate that at least 20 percent of patients with chronic hepatitis C develop cirrhosis, a process that takes at least 10 to 20 years. Liver failure from chronic hepatitis C is one of the most common reasons for liver transplants in the United States. After 20 to 40 years, a small percentage of patients develop liver cancer. Hepatitis C is the cause of about half of cases of primary liver cancer in the developed world. Men, alcoholics, patients with cirrhosis, people over age 40, and those infected for 20 to 40 years are at higher risk of developing HCV-related liver cancer.

Risk Factors and Transmission
Clinical Symptoms and Signs
Serologic Tests
Liver Biopsy
Noninvasive Tests
Diagnosis
Treatment
Considerations: Before, During, and After Therapy
Hope through Research

For More Information

Fact sheets about other conditions are available from the National Digestive Diseases Information Clearinghouse at www.digestive.niddk.nih.gov.

The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services. Established in 1980, the Clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. The NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.

Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This publication was reviewed by Beth Bell, M.D., Centers for Disease Control and Prevention, Atlanta; Marc Ghany, M.D., NIDDK, NIH; Jay Hoofnagle, M.D., NIDDK; David Kleiner, M.D., National Cancer Institute, NIH; Jake Liang, M.D., NIDDK, NIH; John McHutchison, M.D., Duke University; and Leonard Seeff, M.D., NIDDK, NIH.

This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.

NIH Publication No. 07–4230
November 2006