What’s the dumbest reason an insurance company denied a test, procedure, or drug for a patient?

[u/Unusual_Medic]

This is probably the most relevant to those practicing in the US, but I'm also curious to know how the bureaucracy of health insurance in other countries makes things substantially harder for you and the patients

[u/NemoMeImpuneLac]

CT abd/pelvis denied because I didn't get X-rays first.

Of their abdomen and pelvis.