Quest Diagnostics: Hackers Stole Patient Data From Quanum Platform

Quest Diagnostics confirmed on Thursday that hackers accessed sensitive patient information through its Quanum lab ordering platform. The company filed an 8-K with the Securities and Exchange Commission to disclose the breach, which it detected on Wednesday. Quanum serves as a central hub for doctors, hospitals, and other healthcare practices to order lab tests and process billing.

The filing states that unauthorized access included specific patient records. Quest has notified law enforcement and is currently investigating the incident. The company has not yet determined the full scope of the data loss or the start date of the breach. It has also not confirmed whether a hacking group contacted it with ransom demands.

Quest issued a security notice stating that protected health information, including personal details and medical records, was taken. The company is still identifying the specific types of data stolen. A technical detail on the notice page includes a "noindex" code, which prevents search engines from listing the page and makes it harder for the public to find the information.

The potential scale of the exposure is large. Quest materials indicate that about 500,000 clinicians use Quanum across thousands of locations in North America. While the exact number of affected patients is unknown, a 2026 case study on the company’s website describes a single health system using the platform that manages more than 6 million patients and hundreds of millions of medical documents.

This incident adds to a series of major cyberattacks on the healthcare sector in 2026. Earlier this year, Stryker suffered mass device wiping, and Boston Scientific experienced weeks of network downtime. Other breaches this year affected CareCloud, Craneware, and McKesson. Criminal groups frequently target health tech firms to steal data for ransom or resale.

Quest’s spokesperson, Amanda Rivera, directed questions to the security notice rather than answering directly. The company has not disclosed how many healthcare customers or individual patients are affected. This is the second major data breach for Quest in a decade; in 2019, a cyberattack on a third-party billing company resulted in the loss of 11.9 million patient records.