The official definition
“Expenses incurred prior to coverage”
That is the verbatim definition of CARC 26 from the X12 Claim Adjustment Reason Code set, the standardized codes every insurer uses on EOBs and remittance advices. The letters in front of the number are the group code. PR: Patient Responsibility: the insurer says you owe this amount. Verify it against your plan before paying.
What it means in plain English
The insurer says the service happened before your coverage started. Around job changes and plan-year transitions this is sometimes true and often wrong: effective dates get entered incorrectly, and claims get sent to the new insurer when they belonged with the old one.
What to check on your EOB
- Your actual coverage effective date, from your enrollment confirmation or HR, not from memory.
- The date of service on the claim against that effective date.
- Whether the claim was sent to the right insurer; care from before a switch belongs with your previous plan.
What to do next
- If your coverage was in effect, send the insurer proof of your effective date and request reprocessing.
- If the service predates this plan, have the provider bill your previous insurer; most allow claims up to a year after the date of service.
Who's responsible
You + provider. Most denials carry a clear owner. Knowing whether the fix belongs to you, your doctor, or the billing office is half the battle. If it's the provider's error, you should not be paying for it.
Want the fundamentals first? Start with how to read an EOB and the 7 most common billing errors. This page is general information about standardized denial codes, not legal or medical advice.
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