Quest Diagnostics data breach

What happened

Quest Diagnostics disclosed that patient records have been exposed after a threat actor gained unauthorized access to its Quanum LSM system. The company is still investigating the incident but believes some patient records were exposed. On October 21, 2026, Quest Diagnostics Incorporated learned of unauthorized access to its Quanum LSM system, which certain clients use to place test orders, receive and look up results,

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Reported impact

Data access

unknown

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BleepingComputer01

Quest Diagnostics confirms data breach exposed patient records

Retrieved 3 Nov 2026

On October 21, 2026, Quest Diagnostics Incorporated learned of unauthorized access to its Quanum LSM system, which certain clients use to place test orders, receive and look up results

Attributed reporting

1 more excerpt

The company is still investigating the incident but believes some patient records were exposed.

Attributed reporting