When you have Medicare and another type of insurance, Medicare will either pay primary or secondary for your medical costs.
If you are considering delaying Part B enrollment because you have insurance, make sure to ask your benefits manager or human resources department how your insurance works with Medicare. In cases where Medicare is primary to your current insurance, you should enroll in Part B to avoid incurring high costs for your care. This is because when Medicare is primary to your other insurance, your other insurance may not pay for costs until Medicare pays—so you would be responsible for paying these costs out of pocket. When Medicare is secondary, your current insurance will pay the majority of the cost for covered services.
You can also confirm how Medicare works with your current insurance by contacting the Social Security Administration (SSA) or Medicare.