What is MD?

[Unregistered]

In the sentence:

Jane Doe, MD, evaluated the patient for half an hour.

what article of the sentence is "MD?" Does it have a name? I know it is supposed to be separated by two commas, but why?

[pyoung]

MD= medical doctor

[Ouisch]

In the sentence:

Jane Doe, MD, evaluated the patient for half an hour.

what article of the sentence is "MD?" Does it have a name? I know it is supposed to be separated by two commas, but why?

It is an appositive. In this case, "Medical Doctor" describes Jane Doe, but it is not necessary to include it; you could remove the appositive and still have a complete sentence.

[David L.]

I know it is supposed to be separated by two commas, but why?

NO - only one:

Joe Blogs MD, Mayo Clinic.

Jane Doe, MD, evaluated the patient for half an hour.

You wouldn't write/say that. It would just be

Dr. Jane Doe evaluated...