Quest Diagnostics Confirms Theft of Patient Files From Quanum Platform

Quest Diagnostics told U.S. regulators on Thursday that hackers stole patient data from Quanum, its digital platform for ordering lab tests. The company filed an 8-K disclosure with the Securities and Exchange Commission to report the breach. It stated that it learned of the unauthorized access on Wednesday.

Quanum serves as a central hub for doctors' offices, hospitals, and other healthcare practices. These entities use the software to submit test orders and process billing. The system stores large volumes of sensitive information, including patient health records, diagnostic results, and financial data. Quest confirmed that the attackers took specific patient files but did not specify the total volume of data compromised.

In a separate security notice, the company said that protected health information was taken. This includes personal details and medical records. Quest is still determining exactly which data points were accessed. A spokesperson for the company, Amanda Rivera, declined to answer specific questions from reporters. She directed inquiries to the company's online security notice.

That notice page currently contains 'noindex' code. This instruction tells search engines to exclude the page from results. It makes the document difficult for the public to find. Quest has not disclosed how many healthcare customers or individual patients are affected by the breach. It also has not revealed when the attack began or if the hackers have contacted the company with ransom demands.

The potential scale of the incident is large. Quest's materials state that about half a million clinicians use Quanum across thousands of locations in North America. The exact number of stored records is unclear. However, a 2026 case study on Quest's website describes a single health system holding more than 6 million patients and hundreds of millions of related medical documents.

This is the second major data breach for Quest in ten years. In 2019, the company lost 11.9 million patient records due to an attack on a third-party billing vendor. The healthcare sector has faced a series of major cyber incidents this year. Attacks on Stryker, Boston Scientific, CareCloud, Craneware, and McKesson have caused operational disruptions and the theft of millions of patient records.