Official CARC description: “Expenses incurred prior to coverage.” Here’s what it actually means, why it fires, and how to get the claim paid.
The DOS predates the coverage effective date. Twin of CO 27 — same verification-first playbook, opposite direction.
Liability group: CO = Contractual Obligation — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Confirm the effective date on the eligibility response
Retro-enrollment (Medicaid especially): resubmit AFTER enrollment finalises
Wrong date on payer file: have it corrected, then reprocess
Truly pre-coverage: bill the prior plan or the patient
Appealable when retroactive coverage exists (Medicaid retro-eligibility is the big one) — resubmit with the eligibility determination letter.
Fill in the denial facts — use placeholders, never real patient data (the letter keeps [PATIENT NAME]-style fields so you can merge real details privately). A payer-ready draft with an enclosure checklist comes back in ~20 seconds.
Your appeal letter draft will appear here.
Expenses incurred prior to coverage. In practice: The DOS predates the coverage effective date. Twin of CO 27 — same verification-first playbook, opposite direction.
CO stands for Contractual Obligation — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Appealable when retroactive coverage exists (Medicaid retro-eligibility is the big one) — resubmit with the eligibility determination letter.