Md. Code, State Personnel and Pensions § 6–402

(a) Except as otherwise provided by law, a position in the Executive Branch of State government is in the professional service if the position:

(1) requires knowledge of an advanced type in a field of science or learning customarily acquired by a course of specialized intellectual instruction and study; and

(2) normally requires a professional license, advanced degree, or both.

(b) The professional service includes any other position that is determined by the Secretary to be in the professional service.