Quest Diagnostics has confirmed that patient health and personally identifiable information was accessed during a cybersecurity breach, prompting the medical testing giant to temporarily suspend access to several key systems.
The New Jersey-based company announced on Thursday that it disabled access to its Quanum Lab Services Manager (LSM) platform after detecting unauthorized access on Wednesday. The company expects to restore full functionality by Friday. The platform is used by healthcare providers to order laboratory tests and view results.
Quest stated that it believes some patient data was accessed, but the company is still investigating the specific information involved and the number of individuals potentially affected.
A Quest Diagnostics logo is seen on May 10, 2025, in East Rutherford, N.J. (AP Photo/Angelina Katsanis / AP Newsroom)
As a precaution, the company also temporarily paused access to its Essential Insights and LabHQ systems, though it confirmed that no data was accessed on those platforms.
Despite these temporary restrictions, Quest assured that its core business operations remain unaffected and its ability to serve patients has not been materially disrupted.
Healthcare providers who typically rely on Quanum LSM can continue to place orders via paper requisitions or the company’s Quanum eLabs platform, as other electronic ordering systems remain operational.
Quest announced that it has stopped the unauthorized access and is actively working to restore the affected system. The company does not anticipate testing delays for clients who do not use Quanum LSM.
In a filing with the Securities and Exchange Commission on Thursday, Quest stated that it notified federal law enforcement authorities and brought in external cybersecurity experts to assist with the investigation and response.
The company is working to identify affected patients and healthcare providers and will issue notifications as required by applicable law.
Quest Diagnostics, one of the nation’s leading providers of diagnostic testing services, reported approximately $11 billion in revenue in 2025.
This incident follows a previous cybersecurity breach involving a third-party billing provider that potentially exposed the personal information of millions of Quest patients. After the 2019 incident, in which unauthorized access to a system containing information associated with approximately 11.9 million Quest patients was reported via a third-party billing agency, Quest clarified that its own IT systems were not involved. The company has not yet disclosed whether the latest breach will have financial consequences and declined further comment to FOX Business.