Quest Diagnostics says hackers accessed patient records through its Quanum lab-ordering system

Quest Diagnostics, one of the largest diagnostic-testing companies in the United States, said an unauthorized party got into a system that doctors' offices and other clients use to order lab tests and look up results. In an 8-K filed with the SEC on Thursday, the company said it believes the party "accessed certain patient records."

What Quest has said

The filing says Quest learned of unauthorized access to its Quanum LSM system on October 21. It started incident-response procedures, notified federal law enforcement and brought in outside cybersecurity experts. The full scope is still under investigation, and the company says the incident has not materially disrupted its business or its ability to serve patients.

Fox Business, which reported the story Thursday evening, adds details from the company's statement: Quest disabled access to the Quanum Lab Services Manager platform, expects full functionality back as soon as Friday, and also paused two other systems, Essential Insights and LabHQ, as a precaution. According to that report, Quest says no data was accessed on those two. Those points rest on Fox Business's account, not on the 8-K. Quest has not said how many people are affected or what kind of information was taken, and it declined to comment further to Fox.

Who feels it

• Practices that order through Quanum LSM. Per the Fox report, they can place orders with paper requisitions or through Quest's separate Quanum eLabs platform. Other electronic ordering systems are described as running normally.
• Patients whose tests were ordered through the platform. Quest says it is working to identify them and will send notifications as required by law. Nobody outside the company knows yet whether a given person is on that list.
• Practice owners. A clinic that sends patients to Quest is typically the party patients call first. Front-desk staff should expect questions this week.

What to do now

• Do not click links or return calls about "your Quest results" that you did not initiate. Breach news is a common hook for phishing. Wait for a letter or contact Quest through the number on its own website.
• If you receive a breach notice, the Federal Trade Commission's IdentityTheft.gov explains how to place a fraud alert or credit freeze and how to read your insurer's statements for services you did not receive.
• Medical practices: ask your Quest representative in writing which of your patients' records were involved, and check your own breach-notification duties with your compliance adviser.

The stock

Quest (DGX) closed Thursday at $243.28, up 1.82%, the same day it filed its quarterly results and this 8-K, according to Nasdaq quote data. In pre-market trading at 9:00 a.m. ET Friday it was at $238.41, down 2.00% on thin volume. Its 52-week range is $171.18 to $248.84. Fox Business notes the company has not said whether the breach will carry financial consequences.

The company has been here before: in 2019 it disclosed that a collections vendor, American Medical Collection Agency, had reported unauthorized access to a system holding information on about 11.9 million Quest patients. Quest said then that its own systems were not involved. This time the affected system is Quest's own.

Sources: Quest Diagnostics Form 8-K, Oct. 22, 2026; Fox Business, Oct. 22, 2026; SEC EDGAR; Nasdaq quote data. This is general information, not medical, legal or investment advice.