Registered Diagnostic Medical Sonographer® (RDMS®)

The RDMS credential raises the standard of diagnostic medical ultrasound practice worldwide and promotes best practices for enhanced patient safety. The RDMS credential is designed to certify competence in the field of diagnostic medical sonography. By earning the RDMS credential, healthcare professionals gain a critical edge in promoting public safety in ultrasound.

Please consult the information below to learn how to become RDMS certified, the application and examination process, and how certification pertains to your career in medical diagnostic sonography.

RDMS Credential Prerequisites
To obtain the RDMS credential, you must meet the examination prerequisites and pass the physics and a corresponding specialty examination within five years:

Physics Examination:
     • Sonography Principles and Instrumentation (SPI)


Specialty examinations:
     • Abdomen (AB)*
     • Breast (BR)*
     • Fetal Echocardiography (FE)**
     • Obstetrics & Gynecology (OB/GYN)*
     • Pediatric Sonography (PS)**

Note: Applicants may pursue the FE specialty under either the RDMS or RDCS credential. Once you take the examination toward earning either the RDMS or RDCS credential, it cannot be switched.

Important Announcement About the NE and PS Specialties
To adapt to the evolving field of sonography, the ARDMS Board of Directors has approved the decision to begin phasing out the Neurosonology (NE) specialty examination prior to the launch of the first PS examination. Beginning 2015, the NE specialty examination will no longer be available. Click to view the press release about the development of the PS examination.

* The application for On Demand examinations is always open, candidates are provided with a 90 day eligibility period and scores are available directly after completion of the examination.  

** The application for Windowed examinations is only open during certain “windows” of time (see specific examination for details), candidates are provided with an approximately 30 day window of eligibility and scores are available approximately 60 days after the close of the administration.