I wouldn't make that decision for the patient when it isn't my money. I can give them the best medical advice, but they make the decision. In some plans, tests, medications, and nonemergency hospital services ordered by non-network doctors are not covered. But the patient may be stuck with bills as if he were not insured. You have a responsibility to make sure they're aware of that.
Most employers offer at least one such option.
Frequently it's just an issue of the plan needing further information, and this gives the physician a chance to provide it. The process is not meant to be adversarial. Doctors sometimes feel that nonphysician reviewers are calling to challenge their judgment. But usually those reviewers are just working from an algorithm, and they want to find out if there's information that makes this case fit the profile for covering that service. At our plan, coverage can only be denied by a physician, so if additional information is needed, the case is forwarded to a medical director.