CO-42: Charges Exceed Payer's Maximum Allowed Amount
CO (Contractual Obligation)What is CO-42?
CO-42 is a Contractual Obligation code indicating the charges exceed the payer's contractually defined or regulatory maximum for the service within a specific time period. Unlike CO-45 (fee schedule adjustment), CO-42 applies to timing or frequency limits on charges.
Why Does CO-42 Occur?
- Service exceeds the payer's frequency limit for the time period (e.g., one wellness visit per plan year).
- Multiple services on the same date exceed the payer's per-day maximum.
- Charges submitted after a COB adjustment exceed what the secondary will pay.
How to Fix CO-42 Denials
- Review the payer's frequency limits for the specific procedure code.
- If the service exceeds frequency limits, check whether the patient has remaining benefits under a different benefit category.
- If the frequency limit is incorrect, appeal with documentation of the service dates and medical necessity.
- For future claims, track frequency limits in your PM system.
CO-42 by Payer
| Payer | Common RARC | Appeal Deadline | Notes |
|---|---|---|---|
| UnitedHealthcare | Varies | 60 days from remittance | Reconsideration required before formal appeal. |
| Anthem | Varies | 365 days from denial notice | Check state-specific provider manual for variations. |
| Aetna | Varies | 180 days from denial | Strict in-network filing enforcement. |
| Cigna | Varies | 180 days from denial | Cigna COB team: 1-800-244-6224. |
| Medicare | Varies | 120 days (redetermination at MAC) | Five levels of appeal starting with MAC redetermination. |
Related CARC Codes
If you are seeing CO-42, check these related codes: CO-16 (claim differs), CO-45 (fee schedule), CO-29 (timely filing).
Common Questions About CO-42
What does CO-42 mean?
CO-42 indicates charges exceed payer's maximum allowed amount. Check the RARC code on the EOB for the specific reason and follow the resolution steps above.
Can I appeal a CO-42 denial?
Yes. Commercial payers allow 60-365 days to appeal depending on the payer. Gather supporting documentation before filing. Medicare allows 120 days for a redetermination request.
Altair catches CO-42 denials before submission with frequency limit tracking. See how pre-submit claim scoring works.