Denial Facts
Denial reason, “Not medically necessary”

They say you didn't need the treatment. Your doctor says you did.

Your two dates, free

Put in the date on your notice and you get both federal deadlines as calendar dates, and the body that decides your case at the end.

Free, for a "not medically necessary" denial, and it runs entirely in your browser. The date, the plan type and the state you pick are never sent to us and never stored.

I had my surgery scheduled to be in 2 weeks and I just got the call that insurance deemed it “not medically necessary”. How do I go about fighting
We hear this most. r/HealthInsurance, “Surgery denied, how do I fight back?”, read September 3, 2026.

Your insurer calls this “Not medically necessary”. This page is about what that actually means and what you can do about it.

The clock your letter has to describe, in actual dates

Two dates decide how much room you have. You have 180 days from the date on your denial notice to file the internal appeal, and then 4 months from the final internal denial to ask for an independent external review. If waiting would seriously jeopardize your health you can ask for both to be expedited, decided in about 72 hours. Both timeframes are federal, not your insurer's choice, 29 CFR 2560.503-1 (PDF) and 45 CFR 147.136 (PDF), in plain English at HealthCare.gov, and your own denial letter states the ones that govern your plan. The PDFs are the same sections on govinfo.gov, which serves them without a challenge page, so an automated reader can check these two dates as easily as you can.

Data verified September 5, 2026 · CMS Transparency in Coverage Public Use File (PY2026 release, PY2024 claims), data.healthcare.gov — US Government public domain

You are not a rare case, and this is the measured version of that: 3,968,921 claims were denied for this reason in the federal file. It is not unusual, it is not a judgment about you, and it is beaten constantly.

What to do tonight
  1. Find the reason code on your denial letter. For this denial it will be worded as "not medically necessary" or close to it, with a code beside it. Write that code down: it is one of 9 categories in the federal file and the one that decides which argument works. Answer the code, not the diagnosis.
  2. Ask your insurer for the clinical criteria they judged you against. Under 29 CFR 2560.503-1 they have to hand you the claim file and the policy they applied, free, on request, and you cannot argue with a checklist you have never read.
  3. Put both deadlines on your calendar before you go to bed. 180 days from the date on the letter for the internal appeal, 4 months from the final internal denial for external review. The free calculator on this page turns your date into the two calendar dates in about ten seconds. 3,968,921 claims were denied for this reason in the federal file, and the ones that get overturned are overwhelmingly the ones that were still inside the window.

None of those three steps costs anything. Anyone charging you to do them is selling you something you can do yourself in twenty minutes.

Someone who has never examined you read a summary of your file, checked it against a written policy, and decided it didn't qualify. Your doctor examined you and decided it did.

Is this your denial? Look for these words on your letter
“not medically necessary”“does not meet medical necessity criteria”“not medically appropriate”“criteria not met”

Not sure? Work out which denial you have →

The first thing to do. Get the policy they judged you against. You cannot argue with a checklist you have not seen , and they have to give it to you free.
Reason to keep going. This is the denial type independent external review is built for, because an independent reviewer judges it on clinical evidence rather than the insurer's own policy.

What to do about this denial

  1. Get the exact wording. Ask for the specific plan provision and clinical criteria relied on. The plan must supply it free of charge on request.
  2. Answer the reason given, not the diagnosis. An appeal that argues the wrong point fails even when the claim is good.
  3. Get your treating clinician to write the counter. For this denial type especially: a letter of medical necessity citing your records and current clinical guidance is the single most effective document you can add.
  4. Internal appeal first, then external review. Internal generally within 180 days of the denial; external generally within 4 months of the final internal denial.
Why external review matters here: this denial type turns on medical judgment, which is exactly what external review exists for. Your case is judged by an independent organization that does not work for your insurer, and the insurer is required by law to accept the decision. Nationally, 32.8% of external reviews went in the patient's favor, yet only 1 in 14,369 denials ever gets there.

Insurers recording the most "not medically necessary" denials

InsurerStateClaimsShare of that record's categorized denials
Celtic Insurance CompanyTexas382,57813.7%
Molina Healthcare of Ohio, Inc.Ohio320,31533.2%
Superior Health PlanTexas212,74414.7%
Molina Healthcare of Florida, IncFlorida185,85131.5%
Cigna HealthCare of Texas, Inc.Texas182,22119.6%
MOLINA HEALTHCARE OF SOUTH CAROLINA, INCSouth Carolina177,86833.3%
Molina Healthcare of Texas, Inc.Texas177,65832.8%
Absolute Total Care, IncSouth Carolina167,92115%
Celtic Insurance CompanyTennessee158,21412.1%
Ambetter of North Carolina Inc.North Carolina156,32513.9%
Cigna Health and Life Insurance CompanyFlorida133,80616.6%
Ambetter of Magnolia Inc.Mississippi133,43110%
Celtic Insurance CompanyArkansas129,86911.3%
Celtic Insurance CompanyMissouri126,34711.8%
Blue Cross Blue Shield of TexasTexas125,4101%
Blue Cross and Blue Shield of South CarolinaSouth Carolina124,0425.4%
Cigna Health and Life Insurance CompanyTennessee113,23413.5%
Celtic Insurance CompanyKansas100,04613.4%
Cigna Health and Life Insurance CompanyMississippi81,80110.5%
Meridian Health Plan of Michigan, Inc.Michigan80,88911.9%
Buckeye Community Health PlanOhio79,84411.7%
Celtic Insurance CompanyAlabama60,44412.8%
Health Net of Arizona, Inc.Arizona55,31114%
Celtic Insurance CompanyOklahoma45,55513.6%
Wellmark Health Plan of Iowa, Inc.Iowa43,8684.4%
Blue Cross Blue Shield of OklahomaOklahoma40,5552.5%
Ambetter Health of Louisiana, Inc.Louisiana34,59812.9%
QualChoice Life & Health Insurance Company, Inc.Arkansas32,22510.2%
QCA Health Plan, Inc.Arkansas30,2339.9%
Blue Cross Blue Shield of North DakotaNorth Dakota30,03929.8%
Blue Cross and Blue Shield of AlabamaAlabama29,7651.1%
Cigna HealthCare of North Carolina, Inc.North Carolina21,90613.7%
Cigna Health and Life Insurance CompanyIndiana21,33919.8%
Celtic Insurance CompanyNew Hampshire20,57114.2%
Molina Healthcare of UtahUtah20,46834.9%
Sunshine State Health PlanFlorida19,1046.5%
Premera Blue Cross Blue Shield of AlaskaAlaska13,7944.4%
Highmark BCBSD Inc.Delaware11,7605.9%
Highmark Blue Cross Blue Shield West VirginiaWest Virginia11,0195.3%
Blue Cross and Blue Shield of MontanaMontana10,9216.2%
Wellmark of South DakotaSouth Dakota7,9887.5%
Health First Commercial Plans, Inc.Florida7,4691.2%
Blue Cross and Blue Shield of NCNorth Carolina5,5900.2%
Cigna HealthCare of Arizona, IncArizona4,29421%
Summa Insurance Company, Inc.Ohio3,9165.9%
Security Health Plan of Wisconsin, Inc.Wisconsin3,4941.4%
SelectHealth, Inc.Utah3,0510.1%
University of Utah Health Insurance PlansUtah2,6922.3%
Molina Healthcare of Mississippi, IncMississippi2,66536.2%
Blue Cross and Blue Shield of FloridaFlorida2,5300.1%

Where a “not medically necessary” denial is common, and where it is not

Every state whose insurers recorded this reason at all, with how much of that state's categorized denials it accounts for and where it ranks among the reasons recorded there. Computed from the plan-year 2026 release of the CMS file, not quoted from anyone's summary.

StateClaimsShare of that state's categorized denialsRank there
Texas1,082,0794.2%7 of 9
South Carolina469,83111.6%3 of 9
Ohio404,91311.2%4 of 9
Georgia388,0026.7%7 of 9
Florida351,0172.1%5 of 9
Tennessee271,5457.2%6 of 9
Mississippi217,89710%5 of 9
Arkansas192,7326.2%7 of 8
North Carolina183,8373.8%8 of 9
Missouri127,8167%7 of 9
Kansas102,1427.6%7 of 9
Alabama90,4011.7%8 of 9
Oklahoma86,1683.6%6 of 9
Michigan82,3654.8%7 of 9
Illinois77,0293.2%8 of 9
Arizona59,6687.3%6 of 9
Iowa43,8683.3%6 of 9
Louisiana35,3812.2%7 of 9
North Dakota30,48419.5%2 of 9
Utah26,2111.1%8 of 9
Indiana21,4322.3%8 of 8
New Hampshire20,7547.4%5 of 8
Alaska13,8094%5 of 9
Delaware12,7924.9%5 of 9
West Virginia11,0302.1%8 of 9
Montana10,9214.3%5 of 9
South Dakota8,9425.6%6 of 9
Wisconsin5,9710.6%8 of 9
Hawaii2,2771.1%7 of 9
Wyoming1,4760.7%8 of 9
Oregon9760.6%6 of 9
Nebraska1860%9 of 9

A high share here describes what the insurers in that state wrote on their denial notices, not whether those denials were right. The spread runs from Texas at 1,082,079 claims down to Nebraska at 186.

How big this reason is next to the other 8

The same file, the same year, every other categorized denial reason expressed as a multiple of the 3,968,921 claims denied as “not medically necessary”.

Denial reasonClaimsAgainst this page's reason
Other reasons28,113,6317.08×
Administrative reason19,612,2094.94×
Service excluded from the plan10,129,1112.55×
Provider out of network8,567,5752.16×
Referral required7,304,6501.84×
Member not covered5,729,1081.44×
Benefit limit reached3,646,5070.92×
Experimental or investigational101,6120.03×

Your evidence checklist, free, and the whole list

This is what decides a "not medically necessary" appeal. Four of these eleven items are things your plan must hand you free of charge on request under the federal claims procedure regulation. Ask for them before you argue: an appeal written without them is argued against criteria nobody in the room has read. Work down it in order.

What to getWhy it decides the appealWhere it comes from
The denial letter and the Explanation of BenefitsThe stated reason is what your appeal has to answer, and the date on it starts the 180-day clock. Everything else follows from these two facts.You already have it
The complete claim fileEverything relied upon in the decision, and everything submitted, considered or generated while making it, whether or not it was relied upon. 29 CFR 2560.503-1(m)(8)(i) and (m)(8)(ii).The plan, free on request
The medical policy or clinical criteria applied to your claim, with its last review dateThis is the checklist you were actually judged against. (m)(8)(iv) makes the plan's policy for your diagnosis relevant "without regard to whether" the plan relied on it, so it cannot be withheld on that basis. You cannot rebut criteria you have not read.The plan, free on request
The identity and specialty of the reviewer who denied you(h)(3)(iv) entitles you to the identification of medical experts whose advice the plan obtained. (h)(3)(iii) requires the appeal to be decided in consultation with a professional with appropriate training in the field of medicine involved, if it was not, that is an argument in itself.The plan, free on request
The full plan document or Evidence of Coverage in force on the date of serviceSummaries are compressed and are frequently broader than the contract they summarize. Argue from the contract, not the summary.The plan, free on request
Your treating clinician's letter of medical necessityWritten against the plan's own criteria, item by item, once you have the policy. A letter that says "this patient meets criteria 2a, 2c and 3, documented at ..." is worth far more than one asserting the treatment is needed.Your clinician
Medical records evidencing each criterion in the plan's policyThe reviewer is ticking boxes. Point to the page in the record that satisfies each one.Your clinician or records office
Records of treatments already tried, with dates, doses and outcomesPlans deny on the basis that a required step was skipped. Dates, durations and outcomes close that door.Your clinician or pharmacy
Published guidelines or trial evidence for your conditionUnder (h)(2)(iv) the plan must consider everything you submit "without regard to whether" it was in front of the original decision-maker, including evidence that did not exist when they denied you.Free, specialty society and journal sites
A dated log of every call: who you spoke to, what was said, the reference numberDeadline and procedure arguments are won on evidence of what was said and when.You, from today onward
Proof of how and when you sent everythingTracked mail, or the plan's portal with a screenshot of the submission confirmation.You, from today onward
For this denial specifically. Ask for a letter of medical necessity written against the plan's own criteria, send them the policy document you obtained in Step 1. A letter that says "this patient meets criteria 2a, 2c and 3 as documented on ..." is worth far more than one that says the treatment is needed.
Does a "not medically necessary" denial qualify for independent external review? Yes. This is squarely a medical-judgment denial, which is the core category external review exists for. Whatever the answer, your internal appeal rights are unaffected, always run that.
Work out your two deadlines

Put the date from your notice in and get the two calendar dates, with the days remaining.

Runs entirely in your browser, the date you type is never sent to us and never stored. Open the full calculator →

The letter that gets you items 2 to 5, published in full, free

This is the document-request letter, complete and unredacted. It uses four federal rights to make your plan hand over its entire case before you write a word of your appeal. Send this first, whatever your denial reason. The Kit fills it in from your details and pairs it with the letters for the appeal itself, but the letter below works exactly as it stands.

Open the full letter ▸
[Your name]
[Your address]

[Today's date]

[Insurer name]
Appeals Department
[Address from your denial letter]

RE: Request for claim file and plan documents
    Member name: [Your name]
    Member ID: [Member ID]
    Claim / reference number: [Claim number]
    Date of service: [Date of service]
    Date of denial notice: [Date of denial]

To whom it may concern,

I am appealing the denial of the claim above. Before I submit my full appeal, I am
requesting the documents I am entitled to receive, so that my appeal can address the
actual basis of your decision.

Under 29 CFR 2560.503-1(h)(2)(iii), I am entitled, upon request and free of charge, to
reasonable access to and copies of all documents, records and other information relevant
to my claim. Paragraph (m)(8) defines what is relevant. On that basis I request:

1. The complete claim file, including everything relied upon in making this determination,
   and everything submitted, considered or generated in the course of making it, whether or
   not it was relied upon. (m)(8)(i) and (m)(8)(ii)

2. Any statement of policy or guidance held by the plan concerning the denied treatment or
   benefit for my diagnosis, whether or not it was relied upon in this decision. This
   includes the medical policy, clinical criteria, coverage guideline or technology
   assessment applied to my claim, and the date it was last reviewed. (m)(8)(iv)

3. The identification of any medical or vocational experts whose advice was obtained on
   behalf of the plan in connection with this determination, whether or not that advice was
   relied upon, including their specialty and board certification. (h)(3)(iv)

4. The documents demonstrating compliance with the administrative processes and safeguards
   required in making this determination. (m)(8)(iii)

5. The specific plan provision on which the denial relies, and the section of the plan
   document or Evidence of Coverage in which it appears.

6. A complete copy of the plan document or Evidence of Coverage in force on the date of
   service.

Please send these to the address above. I am also giving notice that I intend to appeal,
and I ask that this request not be treated as my appeal or as a substitute for it. I will
submit my full appeal within the applicable deadline.

If you consider that any part of this request falls outside what the regulation requires,
please say so in writing and identify which part and on what basis, rather than declining
the request as a whole.

Sincerely,


[Your name]
[Telephone]

Questions about a "not medically necessary" denial

Is this the denial I have? What words appear on my letter?

Look for these phrases: "not medically necessary", "does not meet medical necessity criteria", "not medically appropriate", "criteria not met". Insurers rarely print the category name itself, they print one of those forms of words. If none of them appear, work through the letter at /what-happened, which sorts denials by the words actually used.

How common is this denial?

3,968,921 claims were denied for this reason in the federal data, 4.6% of all categorized denials. It is not a rare or unusual outcome, and it is not a judgment about you.

Is this denial worth appealing?

Nationally 32.6% of internal appeals and 32.8% of independent external reviews are overturned, and only 1 in 14,369 denials ever reaches external review. This denial type turns on medical judgment, which is precisely the category external review exists for, and the reviewer does not work for your insurer. Both appeals are free, so the cost of trying is your time.

Which insurers record the most of these denials?

Celtic Insurance Company (Texas, 382,578), Molina Healthcare of Ohio, Inc. (Ohio, 320,315), Superior Health Plan (Texas, 212,744). The full ranked table is on this page and free to use. These are counts of denials recorded under this reason, not overturn rates, the federal file does not report appeal outcomes by denial reason.

What evidence should I gather?

The full checklist is published on this page free. The four items your plan must give you free of charge on request are the complete claim file, the medical policy or clinical criteria applied to your claim, the identity and specialty of the reviewer, and the plan document in force on your date of service, under 29 CFR 2560.503-1(h)(2)(iii), (h)(3)(iv) and (m)(8). Ask for a letter of medical necessity written against the plan's own criteria, send them the policy document you obtained in Step 1. A letter that says "this patient meets criteria 2a, 2c and 3 as documented on ..." is worth far more than one that says the treatment is needed.

Of the 9 denial categories in the federal file, "not medically necessary" is the one where people most often argue the wrong point. The single most useful thing on this page is free and takes one paragraph: ask for the criteria they judged you against. An appeal written without them argues against a policy nobody in the room has read, which is a bit like appealing a parking ticket without knowing what the sign said. Get the criteria first. The rest of this page, and the letter published on it, are yours whether or not you ever buy anything from us.

, Andrew at Axion Labs · hello@getaxionlabs.com
Get my Appeal Kit, $29

Everything you need for a "not medically necessary" denial: your two deadlines, the argument that fits your denial reason, the letters, the clinician brief, and the external review request. One payment. No subscription. No cut of your claim. Opens on screen the moment you pay. 14-day refund, no questions, one email to hello@getaxionlabs.com.

Where these numbers come from

The 3,968,921 claims recorded under “not medically necessary”, and the insurer-by-insurer table above, are that file’s own denial-reason columns.

Counts: CMS Transparency in Coverage Public Use File (PY2026 release, PY2024 claims), data.healthcare.gov — US Government public domain. Rights and timeframes: 29 CFR 2560.503-1 (180 days, and your free right to the claim file) and 45 CFR 147.136 (4 months, and what qualifies), explained at HealthCare.gov. Expedited review is decided in about 72 hours under both sections.

Reading either regulation from a script rather than a browser: eCFR answers automated fetches with a challenge page, so the same two sections are mirrored as government PDFs at govinfo.gov (29 CFR 2560.503-1) and govinfo.gov (45 CFR 147.136).

This page presents federal statistics and a general description of appeal rights created by federal law. It is not legal, medical, or insurance advice, and no outcome is guaranteed. Your denial letter and plan documents govern your specific case. Free help is available from your state's Consumer Assistance Program and from the federal Marketplace at HealthCare.gov.

Your words, in a box, read by a person. We ask for no name and no email.