Quest Diagnostics Notifies Regulators of Quanum Platform Intrusion

Quest Diagnostics filed a Form 8-K with the Securities and Exchange Commission on Thursday, disclosing a cyberattack on Quanum, the lab ordering and billing platform used by its healthcare customers. The company said it identified unauthorized access to certain patient records on Wednesday and has reported the incident to law enforcement.

Quanum handles test orders and billing for doctors' offices, hospitals and other practices. Quest materials describe it as a system used by about 500,000 clinicians across thousands of locations in North America. The platform stores patient health records alongside diagnostic and billing data.

The company has not said how many patients or healthcare customers are affected. It also has not disclosed when the intrusion began or whether an attacker has demanded payment. A Quest security notice on its website says some protected health information was taken, including personal information and patient records, and states that the specific categories of data are still being determined. That notice page carries a noindex code, keeping it out of search engine results. Amanda Rivera, a Quest spokesperson, pointed to the notice and did not answer further questions.

A Quest case study published in 2026 describes one health system with more than 6 million patients whose records can generate hundreds of millions of medical documents and charts. Quest has not said how many records were touched in this incident.

The attack is the second major breach involving Quest in the past decade. In 2019, a compromise at a third-party billing vendor exposed 11.9 million patient records. Healthcare technology systems have drawn repeated attacks this year: a March incident at Stryker wiped employee devices, and an August breach at Boston Scientific took its network offline for weeks, which the company called global disruption to operations. Hacks this year also hit CareCloud, Craneware and McKesson.

Quest Diagnostics provides lab testing services. Its shares trade on the New York Stock Exchange under the symbol DGX.