500,000 Clinicians Use Quest Platform Where Hackers Reached Patient Records

Quest Diagnostics confirmed Thursday that hackers accessed patient records through Quanum, the lab ordering platform used by about 500,000 clinicians across thousands of North American locations.

The company disclosed the incident in an 8-K filing with the Securities and Exchange Commission, stating it learned of the attack on Wednesday. Quanum handles test ordering and billing for doctors' offices, hospitals, and other healthcare practices, and stores patient health records, diagnostic data, and related billing information.

Quest said the unauthorized access covered "certain patient records" and that law enforcement has been notified. Its security notice states that some patients' protected health information was taken, including "personal information and patient records." The company has not identified which specific data types were stolen.

The company has not disclosed how many patients or healthcare customers were affected, when the breach began, or whether an attacker has made ransom demands. A spokesperson, Amanda Rivera, referred questions to the security notice. That page carries "noindex" code, which keeps search engines from listing it in results.

Quest's website says Quanum is used by about half a million clinicians. A 2026 case study on the site describes one health system with more than 6 million patients that stores hundreds of millions of medical documents and charts on the platform.

Healthcare has been targeted repeatedly this year. An attack in March wiped employee devices at Stryker, and a hack in August took Boston Scientific's network offline for weeks, causing what the company called "global disruption" to operations. Breaches this year also hit CareCloud, Craneware, and McKesson. Quest's previous major incident was a 2019 attack on a third-party billing company that exposed 11.9 million patient records.