Quest Diagnostics reports cyber breach of patient records

Quest Diagnostics has confirmed a cybersecurity breach involving unauthorized access to its Quanum Lab Services Manager platform. The system is used by healthcare providers to place test orders and retrieve patient results.

The company discovered the breach on Wednesday, October 21, 2026, and subsequently notified federal law enforcement and regulators. While Quest Diagnostics has acknowledged that “certain patient records” and protected health information were accessed, the full scope of the incident remains under investigation.

At this time, the company has not disclosed the total number of affected individuals, the specific types of medical records compromised, or whether the data was downloaded or distributed. Quest is currently working with external cybersecurity experts to investigate the incident and determine the extent of the exposure.