2026 Quest Diagnostics — unauthorised access to Quanum LSM lab-services platform; patient records accessed (SEC 8-K)
Data compromised
Quest believes some patient records were accessed. The data types and the number of people affected have not been determined.
Technical writeup
Verified via Quest’s SEC Form 8-K (filed Oct 23, 2026) and Quest’s notice, as summarised by BleepingComputer. Quanum LSM is Quest’s platform clients use for test orders, results, status tracking and supply orders. Quest has stopped the system, paused Essential Insights and LabHQ as a precaution, and told customers to use paper requisitions or Quanum eLabs. Customer-facing operations and direct LIS and EMR interfaces are reported unaffected. External experts and law enforcement are involved. No threat actor or ransomware claim had been reported as of Oct 23. This is separate from the 2019 AMCA billing-vendor breach (quest-diagnostics2019). recordsAffected 0 (not yet determined).
Root cause
Not disclosed. Quest learned of unauthorised access to its Quanum LSM (Lab Services Manager) system on Oct 21, 2026 and activated its incident response protocol. The access start date is not stated.