Medicare COB: Does Medicare Work Alongside Other Insurance?

In this article...
  • Coordination of benefits refers to what order your health insurance policies pay for services. Find out how Medicare COB works in a variety of scenarios.

Individuals who have Medicare and other insurance coverage may need to be aware of Medicare COB. The COB stands for coordination of benefits, which simply means the coordination of which insurance benefits pay first on any claim. Find out more about insurance COB below to understand when Medicare might pay as primary or secondary.

Understanding Primary vs. Secondary Payer

The primary payer is the insurance company or entity that pays first on a health care claim. When an insurance company or Medicare is the primary payer, it processes the claim normally. That typically means:

  • It considers the charges in question and decides what is allowed and what isn't.
  • What isn't allowed is typically written off by the medical provider.
  • Of the allowed amount, the insurance company pays based on your copay and deductible amount.
  • What's left is considered "patient responsibility."

However, if you have a second insurance policy or other coverage, that payer will kick in as the secondary payer. That means there's a good chance it will pay all or some of the "patient responsibility" left over by the primary insurance.

What's left, if any, after the secondary insurance has processed the claim may be your actual out-of-pocket cost for the services. 

Is Medicare a Primary or Secondary Payer?

Medicare can be either a primary or secondary payer, depending on what other insurance you have and the situation involved in the claim. For those who have Medicare, here are some of the situations when Medicare might be the secondary payer:

  • The medical care you're receiving is due to a workplace illness or injury and workers comp benefits are involved. Workers comp would be the primary payer.

  • The health care you're receiving is due to an auto accident and auto insurance with medical coverage is involved. The auto insurance would pay as primary before Medicare would pay.

  • The medical services you're receiving are due to an accident where liability insurance coverage is involved. The liability insurance would likely be primary.

  • You're older than 65 and have Medicare coverage, but you also have health care benefits through an employer-sponsored plan via your spouse's employment and the employer involved has more than 19 employees.

  • You're younger than 65 and have Medicare coverage because of a disability, but you also have health care benefits through an employer-sponsored plan via your spouse's employment and the employer involved has more than 99 employees.

  • The care you're receiving is covered by black lung benefits, which would pay primary before Medicare.

There's a potential exception to the rules about coverage through employer-sponsored plans. If the employer has joined with others in a union to create a multi-employer health care plan, Medicare will pay secondary if any of the employers in the plan have more than the required employees. 

In most other cases, Medicare pays as the primary insurance and your other coverage kicks in as secondary. Note that if you have coverage through an employer-sponsored plan that wouldn't pay as primary, you typically have to have Medicare Part B coverage for the employer plan to kick in as secondary.

Does Medicare Work Together With Medicaid?

Yes, but Medicaid will always pay as the payer of last resort. This means if you have Medicare and Medicaid, Medicare will pay as primary and Medicaid as secondary. If you have Medicare, another insurance, and Medicaid, Medicaid will only pay after Medicare and the other insurance company have processed the claim.

Does Medicare COB Work With VA Benefits?

No, those who have coverage through both programs must choose a benefit to use each time they seek care. To use VA benefits, you must also go to a VA facility or get preapproval to use VA benefits at a non-VA facility.

How Does Coordination of Benefits Work?

When you seek medical care, ensure you provide all of your insurance information. Claims billing specialists with your doctor's office typically work to ensure they bill claims in the right order according to Medicare COB. 

However, you should also keep Medicare apprised of your benefits status. When you sign up for Medicare, you typically provide some information about your coverage so that Medicare knows how to coordinate your benefits. If your benefits change, you should call the Benefits Coordination & Recovery Center at 1-855-798-2627 to update your information.

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