Quest Discloses Breach of Its Lab Ordering System

Quest Diagnostics filed an 8-K notice with the Securities and Exchange Commission on Wednesday disclosing that its Quanum lab testing system had been breached. Quanum handles test orders and billing for doctors' offices, hospitals and other healthcare practices, and stores patient health records along with diagnostic and billing data.

The company said unauthorized access reached "certain patient records" and that it has notified law enforcement and opened an investigation. A Quest security notice says some patients' protected health information was taken, including "personal information and patient records," though the specific data types remain under review.

Quest has not said how many patients or healthcare customers were affected, when the intrusion began, or whether any group has made ransom demands. Amanda Rivera, a Quest spokesperson, declined to answer questions beyond the security notice. That notice is tagged with "noindex" code, which keeps it out of search engine results.

Quanum is used by about 500,000 clinicians across thousands of locations in North America, according to Quest's own materials. A 2026 case study on the company's website describes one health system with more than 6 million patients whose records can generate hundreds of millions of documents and charts.

Quest has not disclosed how many records Quanum holds. The company has not responded to questions about the number of affected records.

The incident follows a string of attacks on healthcare firms this year. Stryker wiped employee devices in March after an attack, Boston Scientific took its network offline for weeks in August, and breaches were reported at CareCloud, Craneware and McKesson.

Quest suffered a prior breach in 2019, when 11.9 million patient records were lost through a third-party billing company.