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Claim Denials and Appeals for Mental Health Practices

A claim denial is a payer's decision, after processing a claim, to pay less than you billed or nothing at all. An appeal is your formal request that the payer review that decision. The rules for filing one depend on who the payer is.

This guide to claim denials and appeals is for psychotherapists and psychiatrists, solo or group, and for the staff who work the denials. It covers deadlines by payer type, how to read denial codes, what goes in an appeal file, and how to stop the same denial from coming back.

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How long do you have to appeal a denied insurance claim?

The deadline depends on the payer type: at least 180 days for an employer group health plan, 120 days for a Medicare redetermination, and 60 calendar days for a Medicaid managed care plan. The deadline printed on your denial notice always controls.

For claim denials and appeals, write that date down the day the denial arrives. Then find the payer type in the table below. These are the federal frameworks, and plans, contracts and states can add to them. A claim that was rejected before processing is a different problem, and it is not appealed. See the glossary for claim denial terms.

Payer type	Time to file an appeal	Time for the payer to decide	If it is upheld
Employer group health plan (ERISA)	At least 180 days after you receive the denial notice	Post-service: 30 days for a single-level appeal. Urgent: 72 hours.	Next appeal level or external review if the plan or state law provides it
Individual and other non-grandfathered plans (ACA)	180 days after you receive the denial notice	Pre-service 15 days, post-service 30 days. Urgent: final decision within 4 business days.	External review (a request is due within 4 months)
Original Medicare	120 days from receipt of the initial determination (receipt is presumed 5 days after the notice date)	Generally 60 days from the Medicare contractor	Reconsideration by a qualified independent contractor, then three more levels
Medicare Advantage	Set by the plan notice and your contract	Set by the plan	Independent review entity, then administrative law judge, Appeals Council, federal court
Medicaid managed care plan	60 calendar days from the date of the adverse benefit determination notice	Standard: 30 calendar days. Expedited: 72 hours. An extension of up to 14 days is allowed.	State fair hearing, requested within 90 to 120 days of the plan's resolution notice
Medicaid fee-for-service	Set by the state Medicaid agency	Set by the state	State fair hearing

Sources for this table, all checked 10/1/26. ERISA group plans: 29 CFR 2560.503-1. ACA plans: HealthCare.gov internal appeals and HealthCare.gov external review. Original Medicare: CMS.gov redetermination page and CMS.gov appeals overview. Medicare Advantage: CMS.gov managed care appeals. Medicaid managed care: 42 CFR 438.402 and 42 CFR 438.408.

Claim denials and appeals rules by payer type and state

Keep the three families apart. A rule that applies to a commercial plan usually does not apply to Medicare or Medicaid, and Medicaid rules change by state.

Private (commercial) plans

For employer group health plans, the federal claims rule requires a 'full and fair review.' The review must take into account everything the claimant submits, give no deference to the first decision, and be made by someone other than the person who denied the claim or that person's subordinate. When the denial turns on medical judgment, the plan must consult a health care professional with appropriate training and experience. The claimant may also get reasonable access to, and copies of, all documents relevant to the claim (29 CFR 2560.503-1, Cornell LII copy, checked 10/1/26; recheck the current eCFR text). Ask the plan for that claim file before you write the appeal.

Self-funded and fully insured plans, and plans in different states, can differ on external review. Use the denial notice to see which route applies.

Original Medicare

Original Medicare has five appeal levels: redetermination, reconsideration, an Office of Medicare Hearings and Appeals decision, Medicare Appeals Council review and federal district court (CMS.gov, checked 10/1/26). No minimum dollar amount is required to request a redetermination (CMS.gov). CMS also publishes a provider-facing summary (MLN006562). Timely filing for a new claim is a separate rule: see 42 CFR 424.44.

Medicare Advantage

Medicare Advantage plans run their own first-level appeal, and the ladder after that is separate from Original Medicare (CMS.gov, checked 10/1/26). Read both the denial notice and your participation contract, because the contract may set provider dispute rules too.

Medicaid and Medicaid managed care

In Medicaid managed care, the appeal belongs to the enrollee. A provider may file an appeal or grievance on the enrollee's behalf with the enrollee's written consent (42 CFR 438.402, checked 10/1/26). Get that consent before you file. Providers have separate payment dispute processes under their contracts, and those vary by plan. Fee-for-service Medicaid and fair hearing procedures are set by each state, so check the state Medicaid agency's current manual. Never apply one state's deadline to another state.

Parity and benefit limits

The U.S. Department of Labor says most plans cannot apply visit limits to mental health benefits that are more restrictive than those for medical and surgical benefits (DOL parity page). On May 15, 2025, the federal agencies said they will not enforce the new provisions of the 2024 final parity rule while it is under review, and the parity statute and the 2013 rule remain in effect (DOL enforcement statement, checked 10/1/26). Raise a parity concern with the plan in writing, and ask counsel or a compliance officer when real money or legal exposure is involved.

Reading claim denials and appeals: group codes, reason codes and remark codes

On an electronic remittance, a claim adjustment group code says who is responsible for the adjusted amount, and a claim adjustment reason code (CARC) says why it was adjusted.

X12 lists four group codes: CO (Contractual Obligation), OA (Other Adjustment), PI (Payor Initiated Reduction) and PR (Patient Responsibility) (X12 group codes, checked 10/1/26). The reason codes are on X12's CARC list. Read the remittance advice remark codes (RARCs) on the same line, because they add detail the CARC does not. These four reason codes come up often in behavioral health billing.

Code	What it says	Where to start
CO-16	The claim or service lacks information or has submission or billing errors	Find the missing or wrong field. Correct it and resubmit if the payer allows it.
CO-29	The time limit for filing has expired	Pull your proof of timely filing and compare it with the payer's filing rule.
CO-50	Not deemed a medical necessity by the payer	Read the payer's policy. Gather the note and treatment plan. Consider an appeal.
CO-197	Precertification, authorization or notification absent	Check whether an authorization was required and on file. Ask the payer how to request review.

Use the payer's provider manual for what each code means for that payer. The first sorting question is whether the claim was rejected or denied. X12 category code A3 marks a claim returned as unprocessable, and Medicare contractor guidance says an unprocessable claim is corrected and resubmitted, not appealed (X12; First Coast Service Options, a Medicare contractor, checked 10/1/26).

What goes in an appeal file

A strong appeal file in any claim denials and appeals workflow answers the payer's stated reason for denial, point by point, with documents the payer can check.

Copy the denial notice and the remittanceInclude the claim number, dates of service, reason and remark codes, and the appeal deadline. Note the date the notice arrived.
Name the one issueWrite what the payer says is wrong, in one sentence: authorization, medical necessity, coding, enrollment, timely filing or coverage. Appeal that issue, not everything.
Attach the proofSession note, treatment plan, authorization record, proof of timely filing, eligibility check and the corrected claim, as the issue requires. See documentation requirements.
Cite the payer's own policyQuote the policy or contract section the payer relies on, and show how the record meets it. Add the CPT guidance when coding is the issue. See the CPT and E/M code guide.
Say what you wantState the requested action: reverse the denial, reprocess at the correct code, or pay the contracted rate. Sign it and list the enclosures.
Send it and keep proofUse the method the payer requires. Keep proof of delivery. Log the decision due date and the next-level deadline.

For appeals that depend on clinical judgment, the clinician usually needs to review what is sent. Leave clinical conclusions to the treating clinician.

Medicare claim denials and appeals: reopening vs appeal

A Medicare reopening is a request to correct a determination, and it is a different route from a formal appeal.

Under 42 CFR 405.980 (Cornell LII copy, checked 10/1/26), a Medicare contractor can reopen an initial determination within 1 year for any reason and within 4 years for good cause. Parties can request one on the same timelines. The decision whether to reopen is not itself appealable, and contractors handle clerical errors, such as data-entry mistakes and duplicate-claim denials, through reopenings. Ask your Medicare contractor how it wants a reopening submitted, and do not let a reopening request run past the 120-day redetermination deadline if you also need appeal rights.

Preventing denials before the claim goes out

The best way to handle claim denials and appeals is to prevent them, because most denials a practice can control are front-end problems: coverage, authorization, enrollment, coding and filing time.

Check coverage before the first visit. Inactive or wrong coverage is a common cause. See eligibility terms.
Confirm authorization rules. Know whether the plan requires one and what the units and dates are. See authorization terms.
Bill only from your effective date. A claim for a date before your network effective date can deny. See credentialing and in-network vs out-of-network.
Match the code to the note. Time, add-on codes and modifiers must agree with the documentation. See individual psychotherapy codes, add-on codes and modifiers.
Use the right place of service. Telehealth and in-home visits carry their own rules. See place-of-service codes.
Watch the filing limit. Track each payer's timely filing window, and keep proof of the original submission.

Psychotherapists and psychiatrists face different claim denials and appeals

Psychotherapists

Denials center on time-based psychotherapy codes, session limits, authorization and medical necessity. A consistent note and a current treatment plan carry most appeals. See non-E/M CPT codes.

Psychiatrists

Denials often involve the E/M level, the psychotherapy add-on billed with it, and medication management documentation. See E/M codes.

How MCM South Medical Billing Service works denials

What we do

MCM South has billed for mental and behavioral health practices since 2010, and works only with psychotherapists and psychiatrists in solo and medium-size practices. We handle claim denials and appeals: we follow up on denied and rejected claims, prepare appeals, and bill in-network and out-of-network claims for our clients.

See all of our services and who we serve.

Claim denials and appeals FAQ

What is the difference between a claim denial and a claim rejection?

A rejected claim was returned before the payer processed it, because of missing or invalid information, so you correct it and resubmit. A denied claim was processed and refused in whole or in part, so you correct it or appeal. A rejection was never adjudicated, so it generally has no appeal rights.

How long do I have to appeal a denied claim?

It depends on the payer type. Employer group health plans must allow at least 180 days after you receive the denial notice, ACA plans use 180 days for an internal appeal, Original Medicare allows 120 days for a redetermination, and Medicaid managed care allows 60 calendar days. Use the deadline printed on your denial notice.

Can a provider appeal on behalf of a Medicaid managed care enrollee?

A provider may file an appeal or grievance on an enrollee's behalf with the enrollee's written consent. Providers cannot request continuation of benefits that way. Get the consent before you file.

What does CARC CO-50 mean?

CO-50 means the payer did not deem the service medically necessary. Read the payer's policy, collect the session note and treatment plan, and decide whether to appeal. Medical judgment belongs to the treating clinician.

What can I do after an internal appeal is upheld?

Check the denial notice. Depending on the payer, you may have a second internal level, external review by an independent reviewer, a state fair hearing for Medicaid, or the next Medicare level. Each step has its own deadline, so log it as soon as you get the decision.

Sources and date checked

Sources checked 10/1/26. Payer rules, deadlines and form versions change. Confirm against the current source before you rely on one. This page is operational guidance for a billing service. It is not legal advice.

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