Can you provide information on lab services. Who is required to sign off on the report/findings being returned to the ordering physician, would that be the medical director only?

I am not sure if this is a HIPAA question or a question related to specific lab requirements. You would not require written authorization from a patient to release labs to an ordering physician because this would fall under the Payment, Treatment and Operations parameters. There may be requirements here required by CLIA or other governing bodies but that is outside my expertise.