The American Registry for Diagnostic Medical Sonography (ARDMS) is the leading credentialing organization for diagnostic medical sonographers in the United States. ARDMS administers specialty examinations leading to credentials including Registered Diagnostic Medical Sonographer (RDMS), Registered Diagnostic Cardiac Sonographer (RDCS), Registered Musculoskeletal Sonographer (RMSKS), and Registered Vascular Technologist (RVT). ARDMS credentials are widely recognized by employers and are often required for sonographer positions.