Quest Diagnostics Incorporated filed a current report on October 22, 2026, disclosing that on October 21, 2026, it learned of unauthorized access to its Quanum LSM system, which certain clients use to place test orders and receive results.

Key Highlights

  • System affected: The Quanum LSM system, used by certain clients to place test orders, receive, and look up results, was the subject of the unauthorized access.
  • Discovery date: Quest Diagnostics learned of the unauthorized access on October 21, 2026.
  • Patient records accessed: According to the filing, the company believes that an unauthorized party accessed certain patient records.
  • Response actions taken: The company disclosed it initiated cybersecurity incident response procedures, notified federal law enforcement authorities, and engaged external cybersecurity experts.
  • Business operations: The filing states the incident "has not materially disrupted the Company's business operations or its ability to serve patients."
  • Scope under investigation: According to the filing, "the full scope of unauthorized access remains under investigation."

Unauthorized Access to Quest Diagnostics' Quanum LSM System

Quest Diagnostics Incorporated (NYSE:DGX), headquartered at 500 Plaza Drive, Secaucus, NJ 07094, filed an 8-K under Item 8.01 (Other Events) on October 22, 2026, reporting a cybersecurity incident. According to the filing, the company learned on October 21, 2026, that an unauthorized party had gained access to its Quanum LSM system. The Quanum LSM system is described in the filing as one that certain clients use to place test orders, receive, and look up results.

The company disclosed that it "promptly initiated its cybersecurity incident response procedures to contain the activity, assess and investigate the nature and scope of the incident and implement appropriate remedial measures." The filing further states that Quest Diagnostics notified federal law enforcement authorities and brought in external cybersecurity experts to assist with the investigation and response efforts.

As of the filing date, the company reported its belief that an unauthorized party accessed certain patient records, though it noted the full scope of the incident remains under investigation. The filing states the incident has not materially disrupted the company's business operations or its ability to serve patients. The filing was signed by Sean D. Mersten, Vice President and Corporate Secretary, on behalf of Quest Diagnostics Incorporated.

What Was Disclosed

Quest Diagnostics reported unauthorized access to its Quanum LSM system discovered on October 21, 2026, with certain patient records believed to have been accessed. The company has engaged law enforcement and external cybersecurity experts while the scope of the incident remains under investigation.