To get some handle on the wildly-expanding, mostly unregulated world of genetic testing, the federal government established a voluntary registry in which U.S. labs now list about 13,850 tests.

Turns out the volunteer spirit among test makers may not be that strong. According to a new tally from NextGxDx, a Tennessee company that tracks the industry, the total number of tests on the U.S. market is 65,893 – more than quadruple the registry figure, with 8 to 10 new ones coming out every day.

The large number underscores how much genetic testing is changing patients’ lives and the healthcare industry, as the U.S. Food and Drug Administration moves to implement more regulation of the field.

Some tests, such as those that tell women their risk of hereditary breast and ovarian cancer are well validated. But as The Eye has reported, some unregulated tests have led mentally ill patients to make poor drug choices, while others have led some women to abort fetuses they mistakenly believed would be born with serious genetic defects.

“There is no doubt numbers will continue to grow," said Gillian Hooker, vice president of clinical development for NextGxDx, which sells tools to help the health-care industry compare, analyze and order tests. The company counted the number of products on lab testing menus they collect to arrive at their figure.

As for the FDA’s long-standing estimate of 11,000 tests on the market, “we acknowledge that the actual number of tests could be higher or lower,” agency spokeswoman A wrote in an email. “It’s our strong opinion that no one knows how many are out there."

Most genetic tests have escaped regulatory scrutiny of their accuracy and safety because of an exemption in FDA rules. When the agency began regulating diagnostic tests in the mid-1970s, it excluded what was then a small group known as laboratory-developed tests, which were often performed by staff in hospital labs for a small group of patients.

Soon after the sequencing of the human genome in 2003, genetic test makers began using the exemption, which allows them to avoid agency oversight if a test is designed, manufactured and used within a single laboratory.

Since then, many academic, industry and government testing experts agree the number and complexity of tests have dramatically grown. Some tests, including ones that purport to identify Lyme disease and ovarian cancer, have inaccurately identified conditions, according to the FDA.

Industry groups, such as the American Clinical Laboratory Association, oppose the FDA’s proposed rules. They say regulation would stifle innovation and tests would take too long to get to patients.

The larger the number of tests, the longer it could take for the agency to implementing the rules, currently set for a nine-year phase in. However, some genetic testing experts say once the rules begin to take hold, the industry will consolidate and some companies may leave the field rather than face the FDA approval process. The FDA is proposing to more heavily regulate tests that are considered high-risk, such as those that could result in a patient getting the wrong treatment.

“The question is what proportion of those tests would fall into which category," emailed Stuart Hogarth, a senior research fellow at King’s College London, who studies laboratory-developed tests. “Without that data you cannot estimate the likely regulatory workload."

Hooker, of NextDxGx said her company counts every test offered by what is now more than 300 U.S.-based labs. Most tests being offered are competition to existing tests. Many have come on the market after a 2013 U.S. Supreme Court decision that declared genes couldn’t be patented, opening up a less-risky marketplace to test makers.