Final answer:
The correct approach is to determine which insurance is primary, either Medicare or Aetna, and bill that first. This is based on several factors like employment status and age. Billing the incorrect insurance first may lead to payment delays.
Step-by-step explanation:
When a patient has both Medicare and a secondary insurance like Aetna, the billing process involves coordination of benefits (COB). The primary payer, which is usually determined by the rules set by Medicare and the private insurer, must be billed first.
Generally, Medicare is billed first if the patient is over 65 and not currently employed or if the employment is with a small company (<20 employees). If the patient is under 65 and disabled but not working, Medicare is again the primary insurer. Alternatively, if a patient is working and covered by an employer group health plan, or covered under a working spouse's health insurance, that private insurer, possibly Aetna, may be the primary insurer. After the primary insurer has processed the claim, the secondary insurer is billed with the Explanation of Benefits (EOB) or Medicare Summary Notice (MSN) to handle potential remaining costs.
In the scenario described, the most accurate option is to determine which insurance is primary and bill that insurance first. It is not correct to assume that one or the other should always be billed first without considering the specific circumstances. Billing the incorrect insurance initially may result in a delay in payment or denial of the claim.