I just read these and know from my malpractice carrier that if you order an MRI of the brain and the patient doesn't do it, 8 months later has a brain tumor and you didn't followup on the referral, you can be held liable. Seems to me these efforts are fine for normal CXR, labs, EKG but if there's a significant abnormal, a letter would protect you and doesn't have to be certified according to my malpractice carrier which is run by physicians.
