Kidney Immuno Billing

[Guest guest]

For immunos covered under Part B, isn't the remaining 20% to be billed to the

patient's secondary medical plan?

My situation is: patient has Medicare (A,B,D) primary, BC/BS of IL secondary,

and IL Cares RX additionally. Shouldn't the BC/BS of IL be picking up the 20%

for immunos at the pharmacy?