When an insurance company wrongly denies a medical claim, the effect is to shift the cost of that treatment to either the healthcare provider or the patient or both. The best way to challenge the denial is for the provider and the patient to work together in coordinating their arguments and information as to why the claim should be paid. For various reasons, it isn't always possible for the hospital or doctor to work with the patient. But the best results usually occur when the provider and the patient work together rather than separately to challenge insurance denials.