June 3 (UPI) -- The world's largest blood-testing firm said Monday a security breach has compromised the sensitive personal information of nearly 12 million patients.
Quest Diagnostics said the breach last month compromised Social Security numbers and other personal information.
The company said an "unauthorized user" gained access through bill-collecting contractors American Medical Collection Agency and Optum360. The breach was first reported May 14 but the scale of the attack wasn't known until Friday, officials said.
Quest said it's "working with forensic experts to investigate the matter" and has suspended collection requests to AMCA.
Details have been scarce, so far. Officials said Monday the unauthorized activity was first reported May 14 but the scale of the attack wasn't known until Friday.
Quest provides testing for about half of all doctors and hospitals in the United States, CBS News reported.