Claims Guide

Health Insurance Denial

ACA-compliant plans provide federally guaranteed appeal rights — internal appeal plus external IRO review. The 10-step workflow, medical-necessity strategy, the No Surprises Act, and when to escalate to your state DOI or an attorney.

⚠ 180-day internal appeal deadline

Under ACA-compliant plans, you have at least 180 days from the date of denial to file an internal appeal. Missing this deadline forfeits your appeal rights. Calendar the deadline the day you receive the denial.

This content is educational and is not legal, financial, or insurance advice. Coverage decisions depend on your specific situation, risk tolerance, and the actual policy contract you’re offered. For a binding recommendation, speak with a treating physician (for medical necessity letter), patient advocate, or attorney specializing in health insurance, or contact your state Department of Insurance.

The 10-step appeal workflow

1
Get the denial reason in writing — the Explanation of Benefits (EOB)
The EOB or denial letter must state the specific reason for denial and reference the policy provision or clinical guideline supporting it. If you received the denial by phone, request a written EOB immediately. The denial reason determines which appeal path applies: medical necessity, prior authorization, out-of-network, coding error, etc.
2
Confirm whether the plan is ACA-compliant and your appeal rights
ACA-compliant plans (individual marketplace, most employer plans subject to ACA) provide federally guaranteed appeal rights: at least one level of internal appeal and access to external (Independent Review Organization, IRO) review. Self-funded employer plans subject to ERISA have similar but somewhat different rules. Short-term limited-duration plans, faith-based health sharing ministries, and some other plans don't have ACA appeal protections.
3
Calendar the 180-day internal appeal deadline
Under ACA-compliant plans, you have at least 180 days from the date of denial to file an internal appeal. Standard internal appeals must be decided within 30 days for pre-service requests, 60 days for post-service. Expedited appeals (urgent care situations) must be decided within 72 hours. Missing the 180-day deadline forfeits your appeal rights.
4
Gather supporting evidence — especially clinical documentation
For medical-necessity denials, the most valuable evidence is your treating physician's letter of medical necessity (LMN) explaining why the treatment is appropriate for your specific condition. Add: peer-reviewed clinical literature supporting the treatment; clinical practice guidelines from medical societies; documentation of prior treatments tried and failed; the specific diagnoses involved (ICD-10 codes); and the procedure codes (CPT) being denied.
5
Submit the internal appeal in writing
Most insurers have a specific appeals address or portal. The appeal should: state explicitly that it's an appeal (not a request for reconsideration); identify the claim/service being appealed; respond to the specific denial reason; cite the supporting evidence; and request specific relief (full coverage of the service). Keep copies of everything. Track the appeal via certified mail or insurer portal confirmation.
6
Request an expedited appeal if care is urgent or denied for an active treatment
Expedited appeals must be decided within 72 hours under ACA rules. Your treating physician can certify the situation as urgent. Don't accept a standard timeline for urgent care — explicitly request expedited review.
7
If internal appeal is denied, request external (IRO) review
After exhausting internal appeals, ACA-compliant plans must offer external review by an Independent Review Organization — a panel of physicians independent of the insurer. External review is typically free to the policyholder; the insurer pays. External review must be requested within 4 months of the final internal denial. The IRO decision is binding on the insurer (they must follow it) but you can pursue further action if denied.
8
Check whether the No Surprises Act applies (out-of-network billing)
The federal No Surprises Act (effective 2022) protects patients from surprise out-of-network bills in emergency situations and from out-of-network ancillary providers (anesthesiologists, radiologists, etc.) at in-network facilities. If you received an out-of-network bill in these situations, you may be protected — the insurer and provider negotiate through an independent dispute resolution process, not by billing you. CMS has a complaint process for No Surprises Act violations.
9
File a complaint with your state Department of Insurance
After exhausting insurer appeals, file a written complaint with your state DOI. DOIs investigate whether the insurer followed regulatory requirements (timeliness, communication, evidence consideration). Many disputes resolve in the complaint stage. For ERISA self-funded plans, the Department of Labor (EBSA) is the federal regulator.
10
Consider professional escalation if claim is large or denial appears unreasonable
A policyholder-side attorney specializing in health insurance can pursue litigation for unreasonable denials, especially for high-dollar claims (organ transplants, oncology, complex surgeries). Some attorneys take cases on contingency. State unfair claim settlement practices laws and ERISA fiduciary duty rules provide additional remedies in some situations.

Questions to ask the health insurance appeals department

Use these before binding a new policy, at renewal, or whenever you're unsure what your current coverage actually does.

1What specific policy provision or clinical guideline supports this denial?
2What's the deadline for an internal appeal, and where do I submit it?
3Can my treating physician submit a letter of medical necessity directly?
4Is expedited review available given the urgency of my situation?
5After internal appeal, is external IRO review available — and is there a fee?
6If this is an out-of-network billing situation, does the No Surprises Act apply?
7What documentation should I include for the strongest internal appeal?

General claim-denied guide

Universal denial-response workflow

Denial reasons explained

17 common denial reasons with rebuttal evidence

Health insurance hub

HMO/PPO, ACA, COBRA, HSAs, prior authorization

State DOI complaint

When to escalate to your state regulator

FAQ

How long do I have to appeal a health insurance denial?: Under ACA-compliant plans (most individual marketplace plans and most employer plans), you have at least 180 days from the date of denial to file an internal appeal. After exhausting internal appeals, you have 4 months to request external (IRO) review. Non-ACA-compliant plans (short-term, ministry plans) may have shorter deadlines or no guaranteed appeal rights — read the policy or EOB for the specific deadline.
What's the difference between an internal appeal and external review?: Internal appeal is conducted by the insurer itself (or an internal reviewer). External review is conducted by an Independent Review Organization (IRO) — a panel of physicians not employed by or paid by the insurer. External review is required for ACA-compliant plans after internal appeals are exhausted, and the IRO's decision is binding on the insurer. External review is typically more independent and reverses denials more often than internal appeals.
Does my doctor need to write something for my appeal?: Strongly recommended. A letter of medical necessity (LMN) from your treating physician is often the single most important piece of evidence for medical-necessity denials. The LMN should explain: your specific diagnosis; why this treatment is appropriate for your condition; what alternatives have been tried; and why the denied treatment is the best clinical option. Generic appeal letters without physician support have much lower success rates.
What is the No Surprises Act and when does it apply?: The federal No Surprises Act (effective January 2022) protects patients from surprise out-of-network bills in three situations: (1) emergency services at any hospital; (2) out-of-network ancillary services at an in-network facility (anesthesia, radiology, pathology, neonatology, etc.); (3) air ambulance services. In these cases, the patient pays only the in-network cost-sharing amount, and the insurer and out-of-network provider negotiate the rest through an independent dispute resolution (IDR) process. If you received a surprise bill that violates the Act, contact your insurer first and CMS at 1-800-985-3059 to file a complaint.
Can my insurer deny a treatment my doctor says I need?: Yes — insurers regularly deny treatments their medical reviewers consider not medically necessary even when a treating physician recommends them. The dispute centers on the insurer's medical-necessity criteria vs the physician's clinical judgment. The appeal process (internal then external IRO review) is the formal mechanism for resolving these disputes. External IRO reviewers — independent physicians with relevant specialty expertise — overturn a significant portion of medical-necessity denials. Don't accept the initial denial as final, especially for serious or expensive treatments.

Related guides and tools

Jennifer Walsh

Editorial Lead, Health & Medicare

This article was researched and written by the Cover Forge USA editorial team against federal sources (NAIC, CMS, FEMA, DOL, SSA, state DOIs) and standard policy forms. Bylines organize content by topic — they do not assert individual licensure. See our editorial-policy for details.

Reviewed 2026-06-14

Important Disclaimer

This site provides general educational information only and is not a substitute for professional insurance advice. All rates, data, and coverage details are estimates and may not reflect your actual premiums. Insurance availability and pricing vary by state, insurer, and individual risk factors. Always consult a licensed insurance professional in your state before making coverage decisions.

The 10-step appeal workflow

Get the denial reason in writing — the Explanation of Benefits (EOB)

The EOB or denial letter must state the specific reason for denial and reference the policy provision or clinical guideline supporting it. If you received the denial by phone, request a written EOB immediately. The denial reason determines which appeal path applies: medical necessity, prior authorization, out-of-network, coding error, etc.

Confirm whether the plan is ACA-compliant and your appeal rights

ACA-compliant plans (individual marketplace, most employer plans subject to ACA) provide federally guaranteed appeal rights: at least one level of internal appeal and access to external (Independent Review Organization, IRO) review. Self-funded employer plans subject to ERISA have similar but somewhat different rules. Short-term limited-duration plans, faith-based health sharing ministries, and some other plans don't have ACA appeal protections.

Calendar the 180-day internal appeal deadline

Under ACA-compliant plans, you have at least 180 days from the date of denial to file an internal appeal. Standard internal appeals must be decided within 30 days for pre-service requests, 60 days for post-service. Expedited appeals (urgent care situations) must be decided within 72 hours. Missing the 180-day deadline forfeits your appeal rights.

Gather supporting evidence — especially clinical documentation

For medical-necessity denials, the most valuable evidence is your treating physician's letter of medical necessity (LMN) explaining why the treatment is appropriate for your specific condition. Add: peer-reviewed clinical literature supporting the treatment; clinical practice guidelines from medical societies; documentation of prior treatments tried and failed; the specific diagnoses involved (ICD-10 codes); and the procedure codes (CPT) being denied.

Submit the internal appeal in writing

Most insurers have a specific appeals address or portal. The appeal should: state explicitly that it's an appeal (not a request for reconsideration); identify the claim/service being appealed; respond to the specific denial reason; cite the supporting evidence; and request specific relief (full coverage of the service). Keep copies of everything. Track the appeal via certified mail or insurer portal confirmation.

Request an expedited appeal if care is urgent or denied for an active treatment

Expedited appeals must be decided within 72 hours under ACA rules. Your treating physician can certify the situation as urgent. Don't accept a standard timeline for urgent care — explicitly request expedited review.

If internal appeal is denied, request external (IRO) review

After exhausting internal appeals, ACA-compliant plans must offer external review by an Independent Review Organization — a panel of physicians independent of the insurer. External review is typically free to the policyholder; the insurer pays. External review must be requested within 4 months of the final internal denial. The IRO decision is binding on the insurer (they must follow it) but you can pursue further action if denied.

Check whether the No Surprises Act applies (out-of-network billing)

The federal No Surprises Act (effective 2022) protects patients from surprise out-of-network bills in emergency situations and from out-of-network ancillary providers (anesthesiologists, radiologists, etc.) at in-network facilities. If you received an out-of-network bill in these situations, you may be protected — the insurer and provider negotiate through an independent dispute resolution process, not by billing you. CMS has a complaint process for No Surprises Act violations.

File a complaint with your state Department of Insurance

After exhausting insurer appeals, file a written complaint with your state DOI. DOIs investigate whether the insurer followed regulatory requirements (timeliness, communication, evidence consideration). Many disputes resolve in the complaint stage. For ERISA self-funded plans, the Department of Labor (EBSA) is the federal regulator.

Consider professional escalation if claim is large or denial appears unreasonable

A policyholder-side attorney specializing in health insurance can pursue litigation for unreasonable denials, especially for high-dollar claims (organ transplants, oncology, complex surgeries). Some attorneys take cases on contingency. State unfair claim settlement practices laws and ERISA fiduciary duty rules provide additional remedies in some situations.

Questions to ask the health insurance appeals department

Use these before binding a new policy, at renewal, or whenever you're unsure what your current coverage actually does.

1What specific policy provision or clinical guideline supports this denial?

2What's the deadline for an internal appeal, and where do I submit it?

3Can my treating physician submit a letter of medical necessity directly?

4Is expedited review available given the urgency of my situation?

5After internal appeal, is external IRO review available — and is there a fee?

6If this is an out-of-network billing situation, does the No Surprises Act apply?

7What documentation should I include for the strongest internal appeal?

FAQ

How long do I have to appeal a health insurance denial?

Under ACA-compliant plans (most individual marketplace plans and most employer plans), you have at least 180 days from the date of denial to file an internal appeal. After exhausting internal appeals, you have 4 months to request external (IRO) review. Non-ACA-compliant plans (short-term, ministry plans) may have shorter deadlines or no guaranteed appeal rights — read the policy or EOB for the specific deadline.

What's the difference between an internal appeal and external review?

Internal appeal is conducted by the insurer itself (or an internal reviewer). External review is conducted by an Independent Review Organization (IRO) — a panel of physicians not employed by or paid by the insurer. External review is required for ACA-compliant plans after internal appeals are exhausted, and the IRO's decision is binding on the insurer. External review is typically more independent and reverses denials more often than internal appeals.

Does my doctor need to write something for my appeal?

Strongly recommended. A letter of medical necessity (LMN) from your treating physician is often the single most important piece of evidence for medical-necessity denials. The LMN should explain: your specific diagnosis; why this treatment is appropriate for your condition; what alternatives have been tried; and why the denied treatment is the best clinical option. Generic appeal letters without physician support have much lower success rates.

What is the No Surprises Act and when does it apply?

The federal No Surprises Act (effective January 2022) protects patients from surprise out-of-network bills in three situations: (1) emergency services at any hospital; (2) out-of-network ancillary services at an in-network facility (anesthesia, radiology, pathology, neonatology, etc.); (3) air ambulance services. In these cases, the patient pays only the in-network cost-sharing amount, and the insurer and out-of-network provider negotiate the rest through an independent dispute resolution (IDR) process. If you received a surprise bill that violates the Act, contact your insurer first and CMS at 1-800-985-3059 to file a complaint.

Can my insurer deny a treatment my doctor says I need?

Yes — insurers regularly deny treatments their medical reviewers consider not medically necessary even when a treating physician recommends them. The dispute centers on the insurer's medical-necessity criteria vs the physician's clinical judgment. The appeal process (internal then external IRO review) is the formal mechanism for resolving these disputes. External IRO reviewers — independent physicians with relevant specialty expertise — overturn a significant portion of medical-necessity denials. Don't accept the initial denial as final, especially for serious or expensive treatments.