Medicaid Claim Denials by State
Overview
Medicaid filing deadlines and denial patterns vary by state: 90–365 days from DOS, most allow 180–365 days. State agencies and MCOs (Centene, Molina, United) enforce different denial codes and procedures. Common codes: CO-50 (discretionary denial), CO-29 (missing info), CO-16 (late), CO-197 (no auth). Appeal deadlines vary by state and MCO.
Key Requirements
- Know Your State Filing Deadline: File claims within 90–365 days from service date. Most states allow 180–365 days. Missing the deadline results in automatic denial.
- Identify the MCO or State Agency: Determine if the claim is processed by your state Medicaid agency or an MCO like Centene, Molina, or United. Denial codes and appeal timelines differ.
- Review Denial Reason: Each denial code indicates a specific issue: CO-50 = medical necessity, CO-29 = missing information, CO-16 = late submission, CO-197 = missing prior auth.
- File Appeal Within State Timeline: Most states allow 30–60 days to appeal from the denial date. Some allow up to 180 days. Verify with your MCO or state agency.
Timeline & Process
Submit claims within 30–60 days of service. Monitor state filing deadline (90–365 days). Upon denial, review reason and gather documentation. File appeal within state window (30–60 days). For medical necessity denials (CO-50), submit clinical justification. For late or incomplete claims, resubmit before filing deadline expires.
Common Denials
| Code | Reason |
|---|---|
| CO-16 | Claim submitted after state filing deadline (90–365 days from DOS). |
| CO-29 | Missing required information (diagnosis, authorization, documentation). |
| CO-50 | Payment denied at MCO discretion (medical necessity not established). |
| CO-197 | Prior authorization not obtained or expired before service. |
Appeal Process
File in writing with the entity that denied claim (state or MCO). Include claim number, explanation, and clinical documentation. Appeal within 30–60 days (some states allow 180). MCOs respond within 30 days. Escalate to state office if MCO denies. Request expedited review (24–48 hours) for time-sensitive services.
Common Questions
What's the filing deadline for Medicaid claims?
Filing deadlines vary by state: 90–365 days from service date. Most states allow 180–365 days. Check your state Medicaid plan documents for your specific deadline.
Why was my claim denied for CO-50?
CO-50 means the service was denied at the payer's discretion—typically due to medical necessity concerns. Appeal with clinical documentation supporting why the service was medically required.
How long do I have to appeal a Medicaid denial?
Appeal timelines vary by state: typically 30–60 days from the denial date. Some states allow longer windows. File early to preserve appeal rights.
Altair checks Medicaid requirements before submission . flagging missing authorizations and coding mismatches in real time. See how Altair works.
This reference is for informational purposes. Payer policies change frequently. Always verify against Medicaid's current provider documentation. Last updated: 2026-03-16.