If you used Quest Diagnostics, your data may have been compromised: Here’s what happened

Published October 22, 2026 1:56 PM MST

Quest Diagnostics said in a regulatory filing that it learned of a data breach that may have exposed certain patient records. (Photo by Smith Collection/Gado/Getty Images)

Quest Diagnostics, a medical laboratory testing company. has confirmed an unauthorized access that may have exposed certain patient records, Reuters reported. 

The backstory:

The breach involved Quest’s Quantum Lab Services Manager system, which some clients use to place orders for tests and to receive and look up test results, the company said in a regulatory filing with the Securities Exchange Commission. 

The full scope of the security breach was not immediately clear, the company said, but it believes that certain patient records were accessed. 

Quest said in a regulatory filing with the Securities Exchange Commission that it learned of the access on Wednesday. At that point, Quest said it began "cybersecurity incident response procedures to contain the activity," assess and investigate and begin remedying the situation. 

"The Company has notified federal law enforcement authorities and engaged external cybersecurity experts to assist in the investigation and response," the document states. 

As the investigation continues, Quest said the breach "has not materially disrupted" business operations. 

Dig deeper:

The Associated Press reported that Quest Diagnostic has been affected by hacks involving patient records in the past. A hack in 2016 exposed data that included lab results and contact information of some 34,000 people. 

Three years later, in 2019, personal data of about 11.9 million Quest patients was affected after a separate hack at American Medical Collection Agency, a billing collections service, the AP said.  

The Source: The information in this article came from Reuters, the Associated Press and the SEC regulatory filing by Quest Diagnostics. This story was reported from Orlando.


 

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