Will new Alzheimer’s tests make the grade?

New drugs for Alzheimer's disease have opened up a secondary market: diagnostics. Up to this point, doctors have relied on invasive tests like positron-emission tomography (PET) scans and cerebrospinal fluid draws to confirm that their patients have the type of misfolded protein the drugs are designed to clear. As the prospect of treatment fuels investment, developers of diagnostics have found simpler and less expensive ways to test for biomarkers with blood samples and digital tools. It's now up to physicians to decide whether to adopt these new tests and for regulators to determine that they're safe and effective. It took Dan Hogan more than 10 years to get a diagnosis of Alzheimer's disease. Troubled by memory issues in 2012, he went to a doctor who ordered a neuropsychiatric exam. That test told him he was "fine," he says. So Hogan coasted along through most of his 70s, even though he