Companies that manufacture or market direct-to-consumer tests must submit their products for premarketing review and approval by the Food and Drug Administration (FDA), according to a series of warning letters sent by the agency in May and June.

The letters indicate a shift in the FDA's approach to the tests, which previously had been marketed to consumers online with little oversight. But letters indicate that the agency considers the tests medical devices that consumers may use to make medical decisions and as such require premarket approval.

"It is important that [the tests] be analytically and clinically accurate so that individuals are not misled by incorrect test results or unsupported clinical interpretations," said Alberto Gutierrez, PhD, of the FDA's Office of In Vitro Diagnostic Device Evaluation and Safety, in warning letters dated June 10.
"Premarket review allows for an independent and unbiased assessment of a diagnostic test's ability to generate test results that can reliably be used to support good health care decisions."

The tests have garnered renewed public attention in recent weeks. In May, Walgreens, the largest drug store chain...