Quest Diagnostics, the world's leading provider of diagnostic information services, has announced the launch of a new test service that helps physicians evaluate a patient's response to drug therapies used to treat infection with the hepatitis B virus (HBV). The first test of its kind available in the United States, the test is significant because it may help physicians tailor more effective treatments for the up to 2.2 million individuals infected with HBV.

Currently, the HBsAg qualitative test is used to aid in diagnosis of patients with HBV. However, this new quantitative test service from Quest measures the quantity, not just the presence, of viral antigen in blood to help determine if the immune system of an individual infected with HBV is responding to treatment. With this insight, physicians are better positioned to monitor response to antiviral medications, and may enable them to modify or adjust treatment to help minimize the likelihood of progression and reactivation.

In a 2016 study published by the European association for the study of the liver's journal of hepatology, researchers noted that, "HBsAg is essential to monitor the response to new therapeutic concepts."

"The widespread availability of quantitative HBsAg testing through Quest for use by hepatologists, gastroenterologists and other specialists will advance the care of HBV-infected patients," said Robert G. Gish, M.D., medical director, Hepatitis B Foundation and Principal, Robert G. Gish Consultants LLC. "The ability to reliably quantify surface antigen will enhance clinicians' ability to stage patient's disease state, provide prognostic information and help guide care with current antivirals and new therapies that are in the development pipeline."

Chronic hepatitis B infection is currently treated with antiviral therapies or interferon alpha (PEG-IFN). Unlike hepatitis C virus infection, in which direct acting antiviral drugs (DAAs) have high success rates, cure rates are lower for HBV due to the persistent nature of the virus and the low compliance rate with long-term therapies. Because viral load may be suppressed during treatment, it cannot be solely considered a sign of viral clearance; resolved chronic HBV is defined by clearance of HBsAg, according to the American Association for the Study of Liver Diseases (AASLD).

"An estimated 850,000 to 2.2 million persons in the U.S. are infected with chronic hepatitis B. While there are effective therapies that can functionally cure HBV infection, physicians in the U.S. have lacked tools that help predict individualized patient response to those treatments," said Rick L. Pesano, M.D., Ph.D., vice president, research and development, Quest Diagnostics. "With this new test capability, physicians can better develop tailored treatment plans and monitor HBV-infected patients to help prevent progression and better their chance for long-term immunity."

The hepatitis B virus can be transmitted by blood, semen, or other body fluid from a person infected with the virus. According to the Centers for Disease Control and Prevention (CDC), chronic Hepatitis B can lead to serious health issues, including cirrhosis or liver cancer.

Quest Diagnostics is a leader in hepatitis diagnostic information testing with services that include genotyping, viral load and antiviral resistance testing to aid diagnosis, treatment and monitoring. The company also collaborates with the CDC to identify trends in screening, diagnosis and treatment for viral hepatitis (hepatitis A, B, C and E) in the United States based on the national Quest Diagnostics Health Trends database of de-identified clinical hepatitis test data.