Health care's alphabet soup: How to decode the letters after your colleagues' names

I retired last year, but I’m still board certified in family medicine until 2029. Although I anticipate staying retired, I do periodically look at LinkedIn, which, honestly, I had never done before, as I’d only been with three health care organizations over a 40-year medical career.

I recently reviewed a post by an M.D., J.D. He completed both medical school and law school in just five years (2005-2010) at two different schools in two different states (New Jersey and Illinois). Wow, now that’s impressive — I’m not sure when he ever slept!

What’s really caught my eye, however, has been the number of postnominal letters listed after the names of so many medical professionals.

For example:

• D.O., FACP, HMDCB, CPE
• D.O., FAAEM, IBFMC, MPH
• D.O., DPM, FRCPC
• M.D., MACP, SFHM
• M.D., MHA, CHCEF, FAAFP
• M.D., FACLM, DABOM
• M.D., M.A., FAAFP
• M.D., FACOG, FAAFM, MSCP
• M.D., MHCM, MJ
• D.N.P., APN, RN, AGACNP, CNOR
• D.M.Sc., ACNP, FAWM, FNAP

The initial letters are straightforward: D.O., M.D., etc. However, others that follow often aren’t, at least to me, so out of curiosity, I spend some time looking them up. See the accompanying decoder for some examples.

The American Medical Association doesn’t specify the number of postnominal letters you should use after your name but recommends that you:

• Include only those that are standard, widely recognized and relevant to your professional identity.
• Avoid unnecessary or obscure letters.

The American Nurses Credentialing Center recommends including all relevant credentials in the following order:

• Highest degree
• Licensure
• State designation
• National certification
• Awards/honors

That helps to explain many of the signature blocks I’ve encountered. For example, “Jane Doe, D.N.P., M.S.N., RN, APRN, FNP-BC.”

I just always noted M.D. after my name. I could have included DABFM (Diplomate of the American Board of Family Medicine) but never did. I had a certificate of added qualifications in geriatrics (CAQ-G) but never included it.

I also could have applied for an FAAFP (Fellow of the American Academy of Family Physicians). I met all the requirements but didn’t because one of the three reasons noted for applying is “the privilege of adding FAAFP initials” to your signature block. It struck me as a ridiculous reason to pay the one-time application fee, which, admittedly, was minimal. That’s a lame excuse, I know.

Years ago, my administrative coordinator gave me some business cards that noted, “Dr. William T. Sheahan, M.D.” I joked with her that I only needed to be a doctor once. She deleted the Dr. prior to my name.

For all those who have a bunch of postnominal letters after their names, thanks. It’s become sort of a game to try to guess what many stand for, prior to looking them up, now that I’m retired.

William T. Sheahan, M.D., is a family physician based in Florida who retired after a 40-year medical career. He earned his medical degree at the University of Virginia School of Medicine and in March 2026 received a foundational certificate in narrative-based medicine from the University of Toronto. He has enjoyed writing on various medical topics over the years. Along with clinical studies and presentations, he is the author of three volumes of Patients Say the Darndest Things and A Doc Who Jots: The More You Know About Your Patient’s Story ….