Quest Diagnostics disclosed Thursday that an unauthorized party reached certain patient records through its Quanum Lab Services Manager system.
The big picture: Quest learned of the intrusion on October 21 and disabled access to Quanum LSM, the platform healthcare providers use to order lab tests and retrieve results, while it investigated.
- The company told the SEC it has notified federal law enforcement and brought in outside cybersecurity experts.
Zoom in: Quest also paused its Essential Insights and LabHQ systems as a precaution and said no data was accessed on either one. It expects to restore full Quanum LSM functionality as soon as Friday.
By the numbers: Quest is one of the largest diagnostic testing providers in the US and reported roughly $11 billion in revenue in 2025.
Yes, but: The company says it has stopped the unauthorized access and that core operations and its ability to serve patients were never materially disrupted. Providers can still order through paper requisitions or the Quanum eLabs platform.
The backstory: In 2019 Quest disclosed that billing vendor American Medical Collection Agency had been breached, exposing information tied to about 11.9 million Quest patients. Quest said its own systems were untouched in that case.
What's next: Quest says it is still working out which patients and providers were affected and how many, and will send notifications as the law requires.
Why it matters: Lab records carry diagnoses, test results and identifiers that follow a person for life. If you use Quest, watch for a breach notice and treat any call or email referencing your test results as suspect until you verify it.
