Here is the wording from their FAQ on Lara site. Keep in mind that the FAQ is not the law but should give you some kind of guideline.
Question: Why do I need to have a physician sign and date a "Physician Certification" form? Why can't I just provide my medical records?
Answer: According to the Michigan Medical Marihuana Act (MMMA), a physician must state in writing that the patient has a qualifying debilitating medical condition and that medical marihuana may mitigate the symptoms or effects of that condition. The MMMP contacts each physician during the application process to verify the patient is under the physician's care. A signed and dated "Physician Certification" must be current within 3 months of the date of a person's new or renewal application.