CPT 99204 is generally covered by all major commercial payers without prior authorization for in-network providers, provided the clinical documentation supports a moderate level of medical decision making (MDM) or 45–59 minutes of total time on the date of the encounter.

Payer Policy Summary for 99204

Payer	State	Coverage	PA Required	Key Criteria / Nuances	Source
Anthem / BCBS	National	Covered	No	Often used in place of non-reimbursable consultation codes (9924x).	Anthem Consultation Services Policy (eff. 07/01/2024)
UnitedHealthcare	National	Covered	No	Subject to "Preventive vs. E/M" bundling logic; if billed with a preventive visit, 99204 may be denied.	UHC E/M Coding Policy (2024)
Aetna	National	Covered	No	Requires "New Patient" status (no service by same specialty/group in 3 years).	Aetna Office Visit Guidelines
Cigna	National	Covered	No	Moderate MDM or time-based (45-59 min) documentation required.	Cigna E/M Reimbursement Policy

🟢 High Confidence

This code is a standard E/M service. Policies are consistent across major payers regarding the lack of prior authorization and the requirement for moderate complexity documentation.

Key Clinical & Billing Requirements

• New Patient Definition: The patient must not have received any professional services from the physician or another physician of the same specialty and subspecialty who belongs to the same group practice within the past three years.
• Documentation Standards:
  • MDM-based: Must meet "Moderate" complexity in 2 out of 3 categories: (1) Number and complexity of problems addressed, (2) Amount and/or complexity of data to be reviewed/analyzed, or (3) Risk of complications and/or morbidity or mortality of patient management.
  • Time-based: Requires 45–59 minutes of total time spent on the date of the encounter (includes non-face-to-face time).
• Prior Authorization: Generally not required for in-network office visits. However, out-of-network providers or specific plan types (e.g., some HMO/EPO plans) may require a referral or authorization for the specialist visit itself.

Common Denials & Risks

• Preventive Overlap: If 99204 is billed on the same day as a preventive medicine exam (e.g., 99385), many payers will deny the 99204 unless a significant, separately identifiable service is documented and appended with Modifier 25.
• Consultation Replacement: Since many payers (like Anthem and UnitedHealthcare) no longer reimburse consultation codes (99241-99245), 99204 is the standard replacement for a high-complexity new patient referral.
• Downcoding Risk: Payers frequently audit 99204 to ensure the "Moderate MDM" is truly supported. If the documentation only supports "Low MDM," the claim may be downcoded to 99203.

Copy for Appeal (Medical Necessity)

"Per [Payer Name] E/M Documentation Guidelines: CPT 99204 is supported by a moderate level of medical decision making. The encounter involved [Number] stable chronic illnesses/acute illness with systemic symptoms and a [Moderate] risk of complications from [Treatment/Management Plan]. Total time spent on the date of encounter was [XX] minutes, meeting the 45-59 minute threshold for 99204."1

Aetna’s prior authorization (precertification) requirements in California vary significantly by plan type (HMO vs. PPO) and the specific service category. For many outpatient procedures, Aetna utilizes EviCore healthcare to manage authorizations.

🔵 Moderate Confidence

Aetna's precertification lists are updated frequently. While the categories below are standard for 2024-2025, you should always verify the specific CPT code via the Aetna Availity portal or Aetna's Precertification Lookup Tool.

---

Key Prior Authorization Categories & CPT Codes (California)

Category	Plan Type	Common CPT/HCPCS Codes	Managing Entity
Advanced Imaging	PPO & Medicare	70450, 70551, 71250, 72141, 74177, 78815 (CT, MRI, PET)	EviCore
Cardiology (ICA/PCI)	PPO & Medicare	93454–93461 (Angiography), 92920–92943 (PCI)	EviCore
Spine Surgery	PPO & Medicare	22551, 22612, 63030, 63047	EviCore
Genetic Testing	All Plans	81406, 81479, 81519 (Oncotype DX)	Aetna Clinical
Behavioral Health	All Plans	H0015, H0018, H0035, 90870 (ECT)	Aetna Behavioral
Sleep Medicine	All Plans	95810, 95811 (Polysomnography)	EviCore
DME / Supplies	All Plans	E2102, E2103 (CGM), A9274 (Insulin Pump)	Aetna Clinical

State-Specific Nuances for California

• EviCore Program: In California, Aetna’s partnership with EviCore for musculoskeletal and cardiology services often applies specifically to PPO members. HMO members may have different authorization paths, often managed through their assigned Medical Group or IPA (Independent Practice Association).
• Medicare Advantage: Aetna Medicare Advantage plans in California generally follow the same precertification list as commercial plans but must also adhere to CMS National Coverage Determinations (NCDs) and Local Coverage Determinations (LCDs).

How to Verify a Specific Code

1. Check the Member ID Card: Determine if the plan is HMO, PPO, or EPO.
2. Use the Aetna Code Tool: Search by CPT code on the Aetna Precertification List.
3. EviCore Portal: For Imaging, Cardiology, and Spine, log in to EviCore.com to check if the specific California plan participates.

Sources

• Aetna 2024 Commercial Precertification List | National/California
• Aetna Medicare Precertification Requirements | California
• EviCore / Aetna Enhanced Clinical Review Program Guide (eff. 2024) | Source URL