Key Takeaways:
- Quest Diagnostics confirmed that a recent cyberattack exposed patients’ personal and health information.
- The company temporarily shut down access to its Quanum Lab Services platform while investigating the incident.
- The company said its main business operations remain unaffected by the attack.
The Quest Diagnostics cyberattack exposed patients’ personal and health information, prompting an investigation. The company temporarily shut down access to some online systems while investigating the incident.
Quest Diagnostics cyberattack exposes patient data
Quest Diagnostics discovered unauthorized access to its computer network on Wednesday. The company found that the incident involved patients’ health records and personal details.
Following the Quest Diagnostics cyberattack, the company launched an investigation to determine how many patients were affected.
Company executives confirmed that unauthorized parties had accessed patient health information and personally identifiable information, which includes details that can identify a person. Investigators are working to determine the full extent of the breach.
Quest Diagnostics is one of the largest providers of medical testing services in the United States. Company reports show that it generated approximately $11 billion in revenue in 2025.
Company shuts down systems as a precaution
The company’s technology teams temporarily disabled access to its Quanum Lab Services Manager platform. Healthcare providers use this software to order laboratory tests and view test results online.
The company also paused access to two other tools, Essential Insights and LabHQ, as a precaution. Officials said no data was accessed on either of these platforms during the incident.
Quest Diagnostics said its main business operations remain unaffected by the temporary shutdowns. Doctors can still order tests using paper forms or other electronic systems.
Clients who do not use the affected platform should not experience testing delays, according to the company. Other electronic ordering tools, including Quanum eLabs, remain available.
The company said it stopped the unauthorized access after discovering the incident. Technical teams are working to restore access to the affected platform, potentially as soon as Friday.
Federal authorities investigate the data breach
Quest Diagnostics filed a report with the U.S. Securities and Exchange Commission (SEC) on Thursday. The company also notified law enforcement authorities about the incident. Its filing outlined the initial findings of the ongoing investigation.
Outside cybersecurity experts have joined the investigation to help protect the company’s computer systems. Quest Diagnostics expects to restore access to the affected platform as soon as Friday.
The company is working to identify the patients and healthcare providers affected by the breach. It said it will notify them as required by law once the review is complete.
The incident follows a separate data breach in 2019 that affected millions of patients. At that time, a third-party billing company, the American Medical Collection Agency, suffered a data breach that affected nearly 12 million patients.
Quest Diagnostics said its internal computer systems were not involved in the 2019 incident.
The company declined to comment further while the investigation continues. It said updates will be shared through its official corporate channels.
