The Gregg Reference Manual says to use a comma to set off abbreviations that follow a person’s name, such as “Jane Doe, CPS.” I recently proofed a newsletter where some names did not have the comma. — Diana
An argument could be made for doing it either way.
Many published style guides, such as the AP Stylebook, say you should always use a comma between a person’s name and any degrees. Example: Jane Doe, M.A. Administrative Professional Today follows AP Stylebook, so we use a comma.
Some editors, though, choose to drop the comma, as IAAP’s OfficePro does. It’s a matter of choosing a rule and sticking with it.