D.C. Mun. Regs. tit. 17, r. 17-5912
Only a person certified by the Board to practice as a nurse-practitioner may use the title or abbreviation "Nurse-Practitioner," "Certified Nurse-Practitioner," or "C.N.P.".
A nurse-practitioner may place the title or abbreviations in § 5912.1 after his or her name, alone or in combination with other letters or words identifying categories of specialization, including, but not limited to, the following:
A speciality area of nursing practice shall be declared, and the specialty title to be utilized shall be the title which is granted by a nationally recognized accrediting body or the title of the specialty area of nursing practice in which the nurse practitioner has received postgraduate educational preparation.
D.C. Mun. Regs. tit. 17, r. 17-5912