CARC 146: Diagnosis was invalid for the date(s) of service reported
The diagnosis code on the claim wasn't valid for the date the service was performed.
What this means for your claim
ICD-10 diagnosis codes are added, revised, and retired over time. If a code that was discontinued or not yet active is used for a given service date, the claim is rejected as a coding error.
What to do next
- 1
Ask your provider's billing office to verify the diagnosis code was active and valid for your date of service.
- 2
Request a corrected claim with the proper ICD-10 code for that service period.
- 3
Confirm a new EOB is issued after the corrected claim is processed.
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 146
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 →