Understanding Your EOBs and ERAs
An Explanation of Benefits (EOB) or its electronic version, the Electronic Remittance Advice (ERA), is the key to understanding why claims are paid or denied. These documents use specific codes to explain how a claim was processed.
Common Remark Codes
- CO (Contractual Obligation): Indicates an in-network adjustment based on an allowed amount.
- PR (Patient Responsibility): The amount the patient owes (deductible, co-pay, co-insurance).
- OA (Other Adjustments): Less common, often related to secondary insurance.
Common Behavioral Health Denial Codes & Solutions
CO4: Modifier Issue
This denial means a modifier is incorrect or missing. Common causes include a missing Modifier 25 on E/M codes billed with add-on services, or incorrect telehealth modifiers (e.g., 95, GT).
CO5: Place of Service (POS) Mismatch
The service code billed doesn't match the location. For example, using office E/M codes for a telehealth visit when the payer requires POS code 02.
CO16 & CO50: Missing Info / Not Medically Necessary
These are vague denials that usually mean the payer needs more information. The solution is to submit detailed chart notes, SOAP notes, or medical history to justify the service.
CO97: Service Bundled into Another
The payer believes the service is part of another procedure already billed. This often happens if Modifier 25 is missing, making it look like two consultations were billed instead of one primary service with an add-on.
CL39, CO62, etc: Authorization/Referral Missing
These denials indicate a missing or expired prior authorization or PCP referral. It's critical to track authorizations (both quantity and date ranges) to prevent this.
CO22 & CO109: Coordination of Benefits (COB) Issue
The payer believes another insurance plan is primary. This is common when patients have multiple plans or have a Medicare Advantage plan instead of traditional Medicare Part B.
Solution: The patient may need to contact their insurance companies to confirm which is primary. If billing Medicare, use the provider portal to identify the correct Medicare Advantage plan.
Billing for Crisis Visits
Using crisis codes (90839 base code, 90840 add-on) can be advantageous, as some plans pay up to three times more for these services. However, other plans may not cover them at all.
Recommendation: Always call the payer to verify coverage and reimbursement rates for crisis codes before billing, and justify their use with thorough documentation.
