Denial Radar

Reference playbook

Decode the denial codes most commonly cited in your segment and the angle to appeal each one. Denial rates can only be measured from your own remits, so contribute your 835s (de-identified, on-device) via the Clean Room to see your real breakdown.

Reddenda holds no denial data for your practice. Nothing on this page is your number.

A denial rate cannot be estimated or benchmarked from public data. It can only be measured from your own 835/ERA remits. The playbook below is X12 code reference, identical for every practice in your segment.

Your denial rate

—

Not measured. No 835s contributed.

Dollars tied up in denials

—

Cannot be inferred. Needs your 835s.

Local-peer denial median

—

Not indexed yet. No contributed peer denials.

Measure it: open the 835 Clean Room →

Commonly-cited denial codes in your segmentX12 reference · not your data

Behavioral-health denials skew to prior authorization, medical necessity, and session/frequency caps. Where a plan applies a limit to BH that it does not apply to comparable medical/surgical care, that is a potential federal parity (MHPAEA) issue, not merely a claims issue.

CO-197Precert / authorization absent

A required prior authorization, precertification, or notification was not on file.

BH is one of the most heavily prior-authorized benefits; auth often has to be renewed mid-course of treatment, and the lapse, not the care, is what denies.

Appeal angle · Supply the auth number if one existed, or request a retro-authorization with clinical justification and any urgent or emergent exception.

CO-50Not deemed a medical necessity

The payer decided the service was not medically necessary as billed.

Medical-necessity denials for BH frequently turn on the plan's internal level-of-care criteria. Request those criteria in writing; plans must disclose them.

Appeal angle · Attach clinical documentation and the applicable coverage policy or LCD showing the service met medical-necessity criteria, and correct any weak diagnosis linkage.

CO-119Benefit maximum reached

The benefit maximum for this time period or occurrence has been reached.

Session or visit caps are the classic parity flag: ask the plan for its quantitative-treatment-limitation comparison against medical/surgical benefits.

Appeal angle · Verify the benefit accumulator. If the maximum was miscounted, provide the correct utilization history.

CO-22May be covered by another payer (COB)

Under coordination of benefits, the payer believes another plan is primary.

Coordination-of-benefits denials are usually resolved on resubmission with the primary's EOB attached.

Appeal angle · Submit an updated COB record or the primary payer's EOB establishing this payer's correct order of liability.

CO-97Bundled into another service

The benefit for this line is included in the allowance for another service that was already adjudicated.

Bundling edits hit BH where a service is treated as inclusive of the therapy session.

Appeal angle · If the services were separate and distinct, append the appropriate modifier (25, 59, or an X{EPSU} modifier) with documentation showing separately identifiable work.

CO-29Timely-filing limit expired

The claim was received after the payer's timely-filing deadline.

Timely filing: the clock for a secondary claim may run from the primary's EOB date rather than the date of service.

Appeal angle · Provide proof of timely original submission (clearinghouse acceptance report) or document a valid good-cause exception.

Appeal deadlines are set per payer and per plan: read the denial letter. The clock usually starts at the remit date, not the date of service, and a corrected claim is often faster than a formal appeal.