Understanding Medical Credentials and Abbreviations
By MedXL Editorial Team · Updated 2026-08-26 · 6 min read
Health care is full of letters: MD, DO, NP, PA, RN, DDS, and dozens more trailing after clinicians' names. Those abbreviations are not decoration; they tell you what kind of training a person has, what they are licensed to do, and who regulates them. This guide translates the most common credentials you will see in the United States and Canada, and shows you how to check them for yourself.
MD stands for Doctor of Medicine. DO stands for Doctor of Osteopathic Medicine, a designation used in the United States. Both are fully licensed physicians. They complete medical school, pass national licensing examinations, and train in residency programs before practicing independently. DOs receive additional training in musculoskeletal manipulation, but in day-to-day practice MDs and DOs work in the same hospitals, prescribe the same medications, and enter the same specialties. In Canada, physicians are generally trained as MDs; US-trained DOs may also be licensed there.
Two other things to look for alongside a physician's degree:
In this guide
- Physicians: MD and DO
- Nurses: RN, LPN/RPN, and NP
- Physician assistants and other prescribing clinicians
- Therapists and mental health credentials
- How to verify any credential yourself
- Red flags and honest limitations
- Key takeaways