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LabCorp Says 7.7 Million Patients Caught in AMCA Data Breach

One day after medical testing firm Quest Diagnostics revealed that nearly 12 million of its patients had their personal and financial information exposed as a result of a breach at the American Medical Collection Agency (AMCA), LabCorp has come forward to say that the incident has also impacted 7.7 million of its customers.

AMCA told SecurityWeek that it’s in the process of investigating “a data incident involving an unauthorized user accessing the American Medical Collection Agency system.” However, the billing collections service provider has not shared any additional details about the attack or how many of its customers have been hit.

AMCA did tell Quest and LabCorp that attackers targeted its payment portal and they had access to its systems between August 1, 2018, and March 30, 2019.

In an 8-K filing with the U.S. Securities and Exchange Commission (SEC) — Quest also disclosed the incident through a SEC filing — healthcare diagnostics company LabCorp said AMCA stored information on roughly 7.7 million of its customers. The compromised information includes name, date of birth, address, phone number, date of service, provider, and balance information.

Attackers may have also accessed credit card or bank account information, but LabCorp said diagnostic information, social security numbers, and insurance information are not stored or maintained for its customers by AMCA. It’s worth noting that AMCA did store social security numbers in the case of Quest.

“AMCA has informed LabCorp that it is in the process of sending notices to approximately 200,000 LabCorp consumers whose credit card or bank account information may have been accessed. AMCA has not yet provided LabCorp a list of the affected LabCorp consumers or more specific information about them,” LabCorp said.

LabCorp learned of the breach from Retrieval-Masters Creditors Bureau, one of the names used by AMCA. LabCorp said AMCA will provide the 200,000 consumers more specific information, along with identity protection and credit monitoring services for two years.

Similar to Quest, LabCorp said it stopped sending any data to AMCA following the disclosure of the breach.

According to, researchers at Gemini Advisory, a company that monitors the dark web for compromised credentials and financial information, came across payment card information for roughly 200,000 individuals. An analysis showed that the data likely came from AMCA, which failed to respond to Gemini Advisory’s notifications, but the company suspended its payment portal after the cybersecurity firm informed federal law enforcement.

This is the second time LabCorp is caught in a cybersecurity incident in the past year. The company was forced to take some of its systems offline in July 2018 due to a ransomware attack.

Related: Lab Testing Firm Eurofins Scientific Hit by Ransomware

Related: Managed Healthcare Provider Humana Discloses Data Breach

Related: Healthcare Firm EmCare Says 60,000 Employees and Patients Exposed in Breach

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.