D.C. Mun. Regs. tit. 17, § 5912
5912.1 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.".
5912.2 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:
5912.3 A specialty 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.
SOURCE: Final Rulemaking published at 36 DCR 3505, 3512 (May 12, 1989); as amended by Final Rulemaking published at 49 DCR 11751 (December 27, 2002).