Quest Diagnostics Pulls Lab Results Platform Offline After Unauthorised Access

Quest Diagnostics, one of the largest clinical laboratory companies in the United States, took a key system offline on Thursday after discovering unauthorised access. The platform, Quanum Lab Services Manager, is used to place test orders and to receive and look up results. The company said it believes some patient data within the system was accessed, and it is still investigating exactly what was affected.

Quest said no other part of the business has been impacted, although several other systems were paused while investigators examine the breach. Customers can use paper requisitions in the meantime, and the company pledged to have the platform running again by Friday. Quest is working with law enforcement, said the incident did not involve the recent PHP vulnerabilities that have worried security experts, and declined to comment on the nature of the incident. No hacking group had claimed responsibility as of Thursday afternoon.

The incident adds to a run of cyber events at healthcare testing firms in 2026. Baylor Genetics recently admitted a breach affecting more than 2.8 million patients, exposing lab results, medical testing information and Social Security numbers. Several electronic health records companies have also been attacked this year. In response, the US Congress passed a bill this month expanding federal cyber requirements for healthcare organisations that handle patient data.