Diagnostics

Quest Diagnostics investigates cyberattack involving patient information

Quest says patient information was involved, but it has not determined which data or how many records were affected.

Reported by 3 outlets Friday, October 23, 2026

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Photo: CC0

Quest Diagnostics said it identified unauthorized access to its Quanum Lab Services Manager system on Wednesday. In a filing with the Securities and Exchange Commission, the company said the system lets certain clients place test orders and receive or look up results. Quest paused access to the system after discovering the incident, notified federal law enforcement and engaged external cybersecurity experts.

Quest said it believes an unauthorized party accessed certain patient records. In an update on its website, the company said patient health information or patient identifiable information was part of the unauthorized access, but it is still determining which data were affected and how many records were involved. Quest said the incident has not materially disrupted its operations or its ability to serve patients.

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