Western Pathology Consultants, Ltd. notified California regulators of a data security incident involving its third-party vendor, Retrieval Masters Creditors Bureau d/b/a American Medical Collection Agency (AMCA). The breach occurred between August 1, 2018, and March 30, 2019, involving unauthorized access to an AMCA database containing patient information. Western Pathology engaged cybersecurity experts and terminated its relationship with AMCA.