Medical testing giant Quest Diagnostics has confirmed a third-party billing company has been hit by a data breach affecting 11.9 million patients. The laboratory testing company revealed the data breach in a filing on Monday with the Securities and Exchange Commission.

Who hacked Quest Diagnostics?

In 2016, the data of 34,000 Quest patients was compromised by a hack on the MyQuest by Care360 internet app. Patients saw their names, dates of birth, lab results, and some phone numbers breached during the security incident.

Did Quest Diagnostics have a data breach?

On May 14th, 2019, American Medical Collection Agency (also called AMCA) informed Quest and Optum360 of potential unauthorized activity on AMCA's web payment page. AMCA is a vendor that provided collection services to Optum360 for debts owed to Quest.