Looking to verify the proper patient responsibility to bill them in the following scenario as well as the proper rationale.

Primary insurance is a high deductible plan through BCBS and allows $ 3000.00 to the patient’s deductible for a patient’s surgery on the $ 5000.00 billed charges. We do not participate with the primary insurance. It’s a PPO plan. They were covered by the out of network benefits on the plan. BCBS says the patient’s responsibility is the $ 5000.00.

Secondary insurance is Medicare and we do participate. Medicare allows $ 1000.00, pays out $ 800 with $ 200 coinsurance. Patient responsibility on remit says $ 200.00.

Do you bill the patient only the 20% coinsurance for $ 200?

Or do you bill the patient for $ 4200.00 ($ 5000.00 minus $ 800.00 paid by Medicare)