Quest Diagnostics Quanum LSM Incident: System Restored, Patient Data Scope Still Under Investigation

Quest Diagnostics disclosed a data breach in its Quanum Lab Services Manager system, exposing patient records, including names, Social Security numbers, and medical information. The breach was contained, but the exact number of affected individuals is still under investigation. Quest will notify impacted patients and offer identity theft monitoring services. The company serves 1 in 3 American adults annually.

Quest Diagnostics reported unauthorized access to its Quanum Lab Services Manager system, exposing patient records. The breach was discovered on Oct. 21, 2026, and disclosed the next day. The company is investigating with outside experts and has notified law enforcement. No disruption to customer operations was reported, and no threat group has claimed responsibility. Quest has temporarily paused access to affected systems and recommended alternative methods for orders and results.

Quest Diagnostics confirmed a security breach exposing patient records via its Quanum Lab Services Manager system. The breach, discovered on October 21, impacted protected health information and personal data. The company has taken steps to contain the breach, but the full extent of the damage is still under investigation. This incident is part of a broader surge in global cyberattacks, including a critical flaw in the PHP programming language.

Quest Diagnostics reported Q3 2026 revenue of $3.1B, up 10% YoY, with diluted EPS rising to $2.78. Operating income increased to $479M. Year-to-date revenue reached $9.035B, with net income attributable to Quest at $884M. The company maintained strong cash flow and returned capital through buybacks and dividends, but noted rising operating costs and debt.

Quest Diagnostics reported Q3 2026 revenue of $3.1B, net income of $312M, and EPS of $2.78, up 10%, 27.3%, and 28.7% YoY. Requisition volume grew 14.5%, with Corewell Health and Fresenius contributing 9.5 points. Excluding these, volume rose 5% and revenue per requisition increased 1.7%. The company aims for 3% annual cost savings through its Invigorate program.

Quest Diagnostics disclosed unauthorized access to its Quanum Lab Services Manager platform, exposing patient data. The company has severed connections and engaged cybersecurity experts. In 2019, a breach at a third-party vendor affected 11.9 million patients.