Quest Diagnostics Data Breach Alert

Have You Received a Quest Diagnostics Data Breach Notification?

CohenMalad, LLP is investigating a recently reported data breach involving Quest Diagnostics, one of the nation's largest medical laboratory testing companies. Individuals who receive a letter or email notifying them that their personal or medical information was compromised in this breach are encouraged to contact our data breach attorneys as soon as possible.

On October 22, 2026, Quest Diagnostics disclosed that an unauthorized party had accessed its Quanum Lab Services Manager system, a platform used by certain healthcare providers to order laboratory tests and access patient results.

According to reports from the Associated Press and Reuters, Quest discovered the unauthorized access on October 21, 2026, and notified federal law enforcement. The company believes certain patient records were accessed, although the number of affected individuals and the specific information involved have not yet been determined. The investigation remains ongoing.

Quest Diagnostics operates laboratory testing facilities throughout the United States.

While the corporation has not yet shared the names of specific labs compromised by this breach, here are some of the notable facilities that operate under Quest Diagnostics.

• Mid America Clinical Laboratories (MACL), Indiana
• AmeriPath, Indiana and multiple states
• Diagnostic Laboratory of Oklahoma (DLO), Oklahoma
• Sonora Quest Laboratories, Arizona
• Associated Clinical Laboratories (ACL), Pennsylvania
• Dermpath Diagnostics, Multiple states
• Athena Diagnostics, Massachusetts
• Cleveland HeartLab, Ohio
• Med Fusion, Texas
• ReproSource Fertility Diagnostics, Massachusetts
• Quest Diagnostics Nichols Institute, California and Virginia
• Diagnostic Lab of Michigan, Michigan

If you receive a letter or email from Quest Diagnostics or an affiliated organization informing you that your information was affected, our data breach attorney team wants to hear from you.

Our attorneys are reviewing the circumstances surrounding this incident and evaluating potential legal claims on behalf of affected individuals.

Individuals whose personal or medical information was exposed in a data breach may have legal rights, even if they have not yet experienced identity theft, fraud, or other apparent misuse of their information.

Learn your rights and protect your claim.

Contact CohenMalad, LLP data breach lawyers now for a free, confidential consultation. Call 317.636.6481 or contact our attorneys online.

There is no obligation to pursue a claim.