Md. Code, Cts. & Jud. Proc. § 10-305

(a) The type of test administered to the defendant to determine alcohol concentration shall be the test of breath except that the type of test administered shall be: (1) A test of blood if: (i) The defendant is unconscious or otherwise incapable of refusing to take a test to determine alcohol concentration; (ii) Injuries to the defendant require removal of the defendant to a medical facility; (iii) The equipment for administering the test of breath is not available; or (iv) The defendant is required to submit to a test of one specimen of blood under § 16-205.1(c)(1)(ii) of the Transportation Article; or (2) Both a test of the person’s breath and a test of one specimen of the person’s blood if the defendant is required to submit to both a test of the person’s breath and a test of one specimen of the person’s blood under § 16-205.1(c)(1)(iii) of the Transportation Article. (b) The type of specimen obtained from the defendant for the purpose of a test or tests to determine drug or controlled dangerous substance content shall be a blood specimen. (c) Any person who is dead, unconscious, or otherwise in a condition rendering him incapable of test refusal shall be deemed not to have withdrawn consent.