CARC 55: Procedures or services are not compatible with this type of service
The billed procedure can't be performed or billed alongside another procedure that was already paid.
What this means for your claim
Certain procedure code combinations are considered clinically redundant or mutually exclusive. This is enforced through Correct Coding Initiative (CCI) edits.
What to do next
- 1
Ask your provider to check whether the procedures billed are subject to CCI bundling edits.
- 2
If the procedures were genuinely separate and distinct, a modifier may allow separate billing — ask the provider to review and resubmit if appropriate.
- 3
Request a clinical review if you believe the services were clearly separate procedures performed independently.
How to handle a contractual-obligation adjustment
Contractual Obligation (CO) codes describe the part of a claim that is governed by the contract between your insurer and the provider. In most cases the adjustment itself is legitimate — it reflects the agreed network discount, your deductible, your coinsurance, or your copay. The money you should focus on is the patient-responsibility line, because that is the amount you can actually verify, dispute, or have reprocessed.
Confirm the math against your plan documents
Pull your Summary of Benefits and Coverage and your member-portal accumulators. Check that the allowed amount matches the in-network contracted rate and that your deductible, coinsurance, or copay was applied at the correct stage. A surprising number of patient-responsibility errors come from accumulators that didn't update after a prior claim.
Check whether your out-of-pocket maximum was reached
Once you hit your annual out-of-pocket maximum, your coinsurance and copays for covered, in-network services should drop to $0. If an EOB still shows patient responsibility after you've met that limit, call member services and ask for the claim to be reprocessed against your accumulator.
Make sure the service was coded the way it actually happened
A visit coded as a higher-complexity level, or a preventive screening miscoded as a diagnostic (sick) visit, can shift cost onto you. Request an itemized bill, compare the CPT codes to what you actually received, and ask the provider's billing office to correct and rebill any mismatch before you pay.
Your appeal rights for CARC 55
If you believe a contractual adjustment was applied incorrectly — wrong network status, wrong accumulator, or a coding error — start with the provider's billing office for coding issues and your insurer's member services for benefit-application issues. If they disagree, you have the right under the Affordable Care Act to a formal internal appeal, and if that's denied, an independent external review.
Have more codes on your EOB?
Upload your full Explanation of Benefits and our analyzer will identify every adjustment code, explain each one in plain English, and flag anything worth disputing.
Analyze My EOB Free →