Medicaid Prior Authorization State Rules
Overview
Medicaid is state-administered. Most states contract with Managed Care Organizations (MCOs) including Centene, Molina, United, and Aetna to process claims. Prior authorization is required for most non-emergency services. Emergency services, preventive care, and ER visits typically bypass prior authorization. State-specific timelines range from 3–5 days for routine requests to 24–48 hours for expedited requests. MCO coverage rules vary significantly by state.
Key Requirements
- Most Non-Emergency Services: Require prior authorization before delivery. Includes specialist referrals, imaging, surgery, durable medical equipment, and behavioral health.
- Emergency Services: Do not require prior authorization. ER visits, urgent care, ambulance transport, and emergency stabilization are covered without pre-approval.
- Preventive Care: Typically bypass prior authorization. Immunizations, preventive screenings, and wellness visits are usually covered without pre-approval.
- Submission Timeline: Submit prior authorization requests 5–10 business days before scheduled service. Expedited requests: 24–48 hours. Routine: 3–5 business days.
Timeline & Process
Identify whether the patient is in fee-for-service Medicaid or an MCO plan. Contact the MCO or state agency for prior authorization requirements. Submit written requests with clinical documentation supporting medical necessity. Routine prior authorizations are processed within 3–5 business days. Expedited requests (for urgent situations) are processed within 24–48 hours. Always obtain approval before delivering non-emergency services.
Common Denials
| Code | Reason |
|---|---|
| CO-16 | Claim submitted without required prior authorization. |
| CO-29 | Claim denied for missing clinical information supporting medical necessity. |
| CO-50 | Service denied at MCO discretion (medical necessity not established). |
| CO-197 | Prior authorization not obtained or expired. |
Appeal Process
Appeal denied prior authorizations within the state-specific window (typically 30–60 days from denial). Submit a written appeal with additional clinical documentation. Include physician statements explaining why the service is medically necessary. MCOs must respond within 30 days for routine appeals and 72 hours for expedited appeals. If the MCO denies the appeal, escalate to the state Medicaid agency.
Common Questions
Do all Medicaid services require prior authorization?
No. Most non-emergency services require prior authorization. Emergency services, preventive care, immunizations, and ER visits typically do not. Verify with your specific state plan or MCO.
Who processes Medicaid prior authorizations?
Most states contract with Managed Care Organizations (MCOs) like Centene, Molina, United, or Aetna. Some states retain fee-for-service Medicaid processed directly by the state agency.
How long does prior authorization take?
Routine requests: 3–5 business days. Expedited requests: 24–48 hours. Timelines vary by state and MCO. Submit early to avoid service delays.
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.