Except as provided in §§ 10–14A–03 and 10–14B–03 of the State Government Article, a person shall hold a license issued by the Secretary before the person may: Offer or perform medical laboratory tests or examinations in this State; Offer or perform medical laboratory tests or examinations on specimens acquired from health care providers in this State at a medical laboratory located outside this State; or Represent or service in this State a medical laboratory regardless of the laboratory’s location. The Secretary shall issue a letter of exception to a laboratory that: Performs only limited medical laboratory tests or examinations; and Meets the exception requirements in regulations adopted by the Secretary pursuant to this subtitle. For the purposes of this section, “limited medical laboratory tests or examinations” means medical laboratory procedures as defined in regulations adopted by the Secretary pursuant to this subtitle. If preliminary screening procedures are performed by an operator who is trained under § 17–214(k) of this subtitle, an employer: Is not required to obtain a permit or to obtain a letter of exception from the Secretary under this section to perform testing; but Is required before performing preliminary screening procedures, as defined under § 17–214(a) of this subtitle, to register with the Secretary in accordance with requirements adopted in regulations by the Maryland Department of Health.