If someone has two health insurance coverage, how does coordination of benefits work?

My friend was in an auto accident, and the health insurance from the auto insurer is her primary health insurance for the accident. She also has regular health insurance from another company. If the auto insurer pays 80% of her auto accident medical costs, and her secondary insurance normally pays 70% of her medical costs, then how would the secondary insurance treat a $1000 bill, for example? The auto insurer pays $800 of the $1000 bill (80%), but how much would the secondary health insurer pay?

Health Ins will always pay their allowed amount they have for that service after deductables and copays are met. Your secondary ins works the same way.but should pick up the remainder of the bill if your ded and copay are met with them. Always look at the allowed amount for that service if the Physician is not in their network then it was your choice not to go to a provider in the insurance network and therefore the provider can collect from you the uncovered amount if they informed you that they were not a provider for that insurance company prior to your appointment. What ever their car insrance worked out with your company with your consent is how the bill should be paid.

If she has medical coverage on your auto policy, they will be primary for the accident. She will have to check her coordination of benefits on her health insurance policy to see if they will pick up any of the cost after the auto policy pays. Since her health insurance would pay less than her auto policy if they were primary, there probably will not be any additional benefit from her health insurance though.

Auto coverage is NOT "health insurance."