The U.S. Food and Drug Administration is moving to expand its regulatory domain by adding oversight of certain diagnostics it does not regulate today. The agency says thousands of these test are used daily to guide treatment decisions and diagnose disease, and it wants to ensure their validity and advance personalized medicine. We spoke to Nathan Beaver, a partner with Foley & Lardner, about the FDA’s efforts, the implications for diagnostics companies, and why the agency’s plans are being met with some resistance from industry and Congress.