I can't testify to the "best" case management certification, but CCM is one of the most widely recognized. I am a part of the American Association of Managed Care Nurses (aamcn.org), and they offer the CMCN (Certified Managed Care Nurse) prep course for certification which covers CM and Q&UM. It's a good introductory course to care management. It's a self-study course, that's now hosted online. They have a sale running on it until 5/19/2017 to promote the 2017 updates.