Md. Code, State Personnel and Pensions § 25–307

(a) Creditable service on which the allowance of a member is based consists of:

(1) eligibility service, except as provided in subsection (b) of this section; and

(2) credit for unused sick leave as provided in § 20-206 of this article.

(b) A member’s creditable service for a period of regular part-time employment equals the member’s actual employment during that period.