The US Food and Drug Administration, responding to growing concerns that a host of tests for illnesses from cancer to Lyme disease may be inaccurately diagnosing patients, announced Thursday that it intends to regulate many of the tests.

Thousands of tests on the market — including some created in Cambridge and Greater Boston’s thriving biotech industry — take advantage of a legal loophole that exempts their makers from FDA oversight and having to prove the tests do what they claim to. In many cases, doctors and patients are left to decide which tests are legitimate.

The New England Center of Investigative Reporting's Beth Daley and Samantha Costanzo report:

"These tests need to be safe and reliable," said Hamburg.

The long-expected oversight will be phased in over nine years, with the first batch of highest-risk tests subject to FDA review a year after the proposed rules are finalized.