ARDMS awards the RDMS credential (Registered Diagnostic Medical Sonographer) to sonographers who pass the Ultrasound Sonography Principles and Instrumentation (SPI) exam and one or more of the following specialty exams: Abdomen, Obstetrics and Gynecology, Breast, Fetal Echo, or Pediactric Sonography.
The SPI exam is 2 hours long and consists of 110 multiple-choice and semi-interactive console questions. Each of the specialty exams is 3 hours in length and contains approximately 170 multiple-choice questions.