A Diagnostics & Imaging Week Report

Roche Molecular Diagnostics (Pleasanton, California) reported FDA approval of the Roche Cobas TaqMan HBV Test, which the company said is the first assay for quantitating hepatitis B virus DNA to be approved in the U.S.

The test uses Roche's real-time polymerase chain reaction (PCR) technology to quantify the amount of hepatitis B virus DNA in a patient's blood. Doctors may use viral load testing results to establish a baseline level of infection and during treatment as an aid in assessing individual responses to therapy.

Roche noted that widespread application of antiviral therapy along with the hepatitis B vaccine has helped reduce prevalence, but hepatitis B remains a serious and potentially life threatening global disease, potentially resulting in death from extensive liver damage or liver cancer for chronically infected people.

"Viral load testing with an FDA-approved test has long been the standard for managing patients with HIV and hepatitis C," said Teresa Wright, MD, chief medical officer at Roche Molecular Diagnostics. "Availability of this new Roche test enables doctors and laboratories to bring that same level of standardized viral load measurement to hepatitis B treatment."

Because the goal of hepatitis B therapy is to treat until the virus is undetectable in the patient's blood, Roche said it is critical for viral load monitoring tests to be able to quantify very low levels of virus. It also is important for the test to quantify very high levels of virus — higher than 100 million IU/mL, an indicator of the need for more or less aggressive treatment.

The company said the Cobas TaqMan HBV Test can detect the World Health Organization HBV International Standard in plasma and serum as low as 3.5 IU/mL and 3.4 IU/mL, respectively. The test can measure HBV DNA as high as 1.10E8 IU/mL, representing "a significantly broader dynamic range than previously available tests in the U.S."