Quest Diagnostics confirmed a cyberattack on Quanum, its lab-test ordering and billing platform, and said some patients' protected health information was taken. The company disclosed the breach in an 8-K filing with the U.S. Securities and Exchange Commission and said it learned of the attack on Wednesday.
Quest says about half a million clinicians across thousands of locations in North America use Quanum. The stolen data includes "personal information and patient records," but the exact types are still under investigation. Quest has not said how many patients are affected, when the breach began, or whether attackers have demanded payment. It has notified law enforcement.
It is Quest's second major known breach in a decade: in 2019, an attack on a third-party billing company exposed 11.9 million patient records. The incident adds to a string of 2026 healthcare breaches, including Stryker, Boston Scientific, CareCloud, Craneware and McKesson.