# Quest Diagnostics cyberattack on patient records > Live situation record from CLSTR: https://clstr.news/situations/quest-diagnostics-cyberattack-on-patient-records > Updated: 2026-10-24T03:03:46.000Z. Sources: 13. Developments: 2. Quest Diagnostics, a major U.S. medical laboratory operator, disclosed a cyberattack targeting its Quanum Lab Services Manager (LSM) platform. The system is used by approximately 500,000 clinicians across North America to order laboratory tests, view results, and manage billing. The company discovered the intrusion on October 21, 2026, and temporarily paused access to the affected system. Quest confirmed that “certain patient records” and protected health information (PHI) were likely accessed, though the exact number of affected individuals and the specific nature of the compromised data have not yet been determined. Quest Diagnostics has notified federal law enforcement and regulators and is working with external cybersecurity experts to investigate the scope of the incident. While the Quanum LSM platform was suspended, the company stated that core business operations remain functional, and healthcare providers can use alternative methods such as paper requisitions or fax to place orders. ## Timeline ### 2026-10-24: Quest Diagnostics reports cyber breach of patient records Quest Diagnostics confirmed a cyber breach of its Quanum Lab Services Manager platform, exposing certain patient records and protected health information. 2 sources. https://clstr.news/cluster/quest-diagnostics-reports-cyber-breach-of-patient-records ### 2026-10-22: Quest Diagnostics confirms cyberattack compromised patient records Quest Diagnostics reported a cyberattack on its Quanum Lab Services Manager system, potentially compromising patient health information and personal records for an undetermined number of individuals. 11 sources. https://clstr.news/cluster/quest-diagnostics-reports-cyber-breach-affecting-patient-records --- Cite as: Quest Diagnostics cyberattack on patient records. CLSTR, https://clstr.news/situations/quest-diagnostics-cyberattack-on-patient-records