CARC 45 (CO-45) — Charge exceeds fee schedule / contracted amount

CARC 45 — "Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement"#

Official meaning: CARC 45 reads "Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement." It almost always appears with the CO (Contractual Obligation) group code, written as CO-45.

What it means in practice: the provider billed more than the payer's allowed amount under the contract or fee schedule. The difference between the billed charge and the allowed amount is a contractual write-off. Because the group code is CO, that write-off is the *provider's* responsibility and cannot be billed to the patient.

Example: A lab bills $200 for a test. The contracted allowed amount is $120. The payer pays $96 (after an $24 patient coinsurance), and reports CO-45 for the $80 difference. The $80 is written off; only the $120 allowed amount is collectible (payer + patient share).

Is CARC 45 a denial? No — it is an *adjustment*, not a denial. It is expected on nearly every in-network claim and normally requires no action. Appealing a CO-45 is usually pointless because it reflects the agreed contract rate.

When to act:

• The allowed amount looks wrong versus the contracted fee schedule (a loading or contract-configuration error on the payer side). Then you dispute the *rate*, not the adjustment code, by referencing the contract.
• A CO-45 appears on an *out-of-network* claim where you expected a different methodology.

CARC 45 is a key input to net-collection-rate and contractual-allowance analytics in revenue cycle management: tracking CO-45 write-offs against expected contract rates surfaces underpayments and fee-schedule load errors.