Maryland Code, Courts and Judicial Proceedings § 10-1003

(a)(1) In a criminal proceeding, the prosecution shall, upon written demand of a defendant filed in the proceedings at least 5 days prior to a trial in the proceeding, require the presence of the chemist, analyst, or any person in the chain of custody as a prosecution witness.

(2) The provisions of §§ 10-1001 and 10-1002 of this part concerning prima facie evidence do not apply to the testimony of that witness.

(3) The provisions of §§ 10-1001 and 10-1002 of this part are applicable in a criminal proceeding only when a copy of the report or statement to be introduced is mailed, delivered, or made available to counsel for the defendant or to the defendant personally when the defendant is not represented by counsel, at least 10 days prior to the introduction of the report or statement at trial.