Roche Holding AG's DNA test is a safe and effective way to help gauge how well hepatitis B virus treatments are working, U.S. health regulators.

The U.S. Food and Drug Administration said the test, called the COBAS TaqMan HBV Test, would give doctors and other health care providers a new sensitive tool to use in conjunction with other tests. Roche's test is given before therapy begins, then after therapy has begun, the FDA said. It works by extracting, then amplifying, some parts of DNA from human plasma or serum, it added