May 25, 2026 · ~10 minute read

Medicare Advantage External Review (IRE Reconsideration): 2026 Template

The Level 1 denial letter reads like the end of the conversation. The plan looked at the appeal, the plan said no, the letter is sitting on the kitchen table, and somewhere in the small print there is a paragraph about “further review” that does a lot of unspecified work.

What that paragraph never says in plain English is the most useful thing in it: your appeal is already moving to the next level, whether you do anything or not. The plan is required by federal regulation to forward it. The decision is now in the hands of a completely separate organization. That is happening in the days after you got the denial letter, without your signature on anything.

I spend more time than is healthy reading CMS regulations, plan policies, and the gap between what a regulation actually says and what an enrollee actually experiences. Health Informatics is what the degree says. Really it is just being annoyed at how hard the system makes it for the people inside it. This post is what I would tell a family member who just opened a Level 1 denial. What is about to happen automatically, what you can do to influence it, and what to send.

What “external review” actually means in Medicare Advantage

The phrase “external review” gets used loosely. In the ACA marketplace world (and in most ERISA employer plans), “external review” is the independent review you get after your insurer denies an internal appeal, governed by 45 CFR 147.136. That is a different process with different rules.

In Medicare Advantage, what people informally call the “external review” is the Level 2 step in the MA appeals ladder: a reconsideration by an Independent Review Entity, or IRE. It lives in 42 CFR Part 422, Subpart M. The IRE is a CMS contractor, not the plan, and it reviews the case file independently.

If you are reading this because your plan upheld its denial at Level 1, the IRE step is where you are now. If you want the full five-level ladder (plan reconsideration, IRE, ALJ at OMHA, Medicare Appeals Council, federal district court), I wrote it up in the first post in this series: How to appeal a Medicare Advantage prior authorization denial in 2026. This post is just Level 2.

One housekeeping note before going further: I am writing this in May 2026, and the IRE contractor changed this month. That matters for where your case is physically going, so I am putting it next.

What the Maximus to C2C transition means for your case

For roughly two decades, Maximus Federal Services in Pittsford, NY ran the Part C IRE. CMS announced last spring that it was awarding the contract to C2C Innovative Solutions, and the switch took effect May 1, 2026 (see CMS Part C Independent Review Entity page).

In practical terms:

  • Appeal requests received by Maximus on or before April 30, 2026 are still being processed by Maximus. They will continue issuing decisions on that backlog for some period.
  • Appeal requests dated May 1, 2026 or later go to C2C.
  • For a short overlap window you may see correspondence from both contractors. That is expected, not a mistake.

For supplemental evidence you are sending in mid-2026, the practical addresses are:

  • C2C Innovative Solutions (current IRE): P.O. Box 1949, Jacksonville, FL 32231-0053. Portal: partcappeals.c2cinc.com. I would double-check the mailing address on the C2C portal before sending, because the brand new contractor is still updating documentation as of this writing.
  • Maximus Federal Services (legacy backlog only): 3750 Monroe Ave, Suite 702, Pittsford, NY 14534-1302.

From the enrollee's side, the procedural rules under 42 CFR 422 Subpart M did not change with the contractor switch. Deadlines, evidence rules, decision timeframes: all the same. What changed is the name on the envelope.

I am flagging this up front because almost every “how to file an IRE appeal” article online still names Maximus as the contractor. If your family member is following a 2024 or 2025 guide, they are about to mail records to the wrong address.

You probably do not have to “file” anything. The plan already did.

This is the part most people I talk to do not know.

When your MA plan issues a Level 1 reconsideration that fully or partially upholds the original denial, the plan is required to auto-forward the case file to the IRE. You do not request Level 2. You do not fill out a form to start it. The plan does it for you, by regulation (42 CFR 422.590).

The forwarding deadlines the plan has to meet:

  • Standard service or item denial: 30 calendar days from the date the plan received the Level 1 request.
  • Standard payment denial (you already paid out of pocket and want reimbursement): 60 calendar days.
  • Part B drug denial, standard: 7 calendar days, and this one is not extendable.
  • Expedited (urgent) cases: 24 hours.

If the plan blows the Level 1 decision deadline without giving you a determination, that missed deadline itself counts as an adverse decision and the plan still has to forward the file. In other words: silence is not the plan winning. Silence is the plan losing into Level 2.

What this means for you: your job at Level 2 is not “file an appeal.” Your job is to send supplemental evidence directly to the IRE that strengthens what the plan already forwarded. The plan's package is going to contain its own denial reasoning, the original clinical records the plan happened to have, and very little that frames your side. Anything you want the IRE to actually weigh, you have to put in front of it yourself.

The IRE timeline you should expect

Once the IRE has the case, its decision deadlines are:

  • Standard service or item reconsideration: 30 calendar days, extendable up to 14 more days in narrow circumstances.
  • Standard payment reconsideration: 60 calendar days.
  • Part B drug, standard: 7 calendar days, not extendable.
  • Expedited reconsideration: 72 hours, extendable up to 14 days in narrow circumstances.

The expedited timeline applies when applying the standard timeframe could “seriously jeopardize the enrollee's life, health, or ability to regain maximum function.” That is the regulatory language. In plain terms: if your mom is currently in a SNF and the plan is cutting off coverage Friday, this is expedited. If you are fighting a denied reimbursement for a procedure that happened last fall, it is not.

One thing the regulation does not impose: a deadline on the enrollee to submit supplemental evidence. I have seen template sites tell readers they have “10 days” or “14 days” to get evidence to the IRE. That is invented. Subpart M sets deadlines for the plan and for the IRE itself. The enrollee's only practical constraint is the IRE's own decision clock, which is why you want to get supplemental evidence in fast, ideally within a week of the Level 1 denial letter. Not because a rule says so, but because once the IRE issues its decision, you cannot un-issue it.

What to send to the IRE: the template

The IRE is going to receive the plan's case file automatically. What you are sending is supplemental, meaning it should add something the plan did not include or did not weight properly. Re-mailing the same intake forms the plan already has wastes everyone's time.

Here is the checklist I work from:

  1. A cover letter identifying the case.Plan name, member ID, the plan's case or appeal number from the Level 1 denial notice, the date of the Level 1 denial, and a clear statement that you are submitting supplemental evidence for the IRE reconsideration. Date it and sign it.
  2. A copy of the plan's Level 1 denial notice. This is usually CMS Form 10003-NDMCP or the plan's branded version of it. The IRE will have a copy from the plan, but including yours confirms which decision you are responding to.
  3. The treating physician's letter of medical necessity. This is the single most important document. I am giving it its own section below.
  4. Clinical records that support the necessity argument. Progress notes, imaging reports, lab results, prior treatment history, prior conservative care that failed. Be selective. A 400-page records dump is worse than 40 targeted pages with the relevant findings flagged.
  5. Peer-reviewed evidence supporting medical necessity. Specialty society guidelines (AAOS, ACC, NCCN, whatever fits the condition), the relevant Medicare National Coverage Determination or Local Coverage Determination if one exists, and any MCG or InterQual criteria the plan's own denial referenced. If the plan denied citing MCG and your physician's notes actually meet the MCG criteria the plan cited, point that out explicitly.
  6. A written statement of why the plan's reasoning was wrong. This is your argument, separate from the physician's letter. Quote the specific sentence in the denial notice you are rebutting and respond to it.
  7. Appointment of Representative form (CMS-1696) if a family member or advocate is filing on the enrollee's behalf. The IRE will not talk to an adult child about a parent's case without this on file. If you already submitted it at Level 1, the plan should have included it in the auto-forwarded file, but I would re-submit a fresh copy anyway. Forms get lost.

Send everything to the current IRE (C2C in mid-2026) by a tracked method. Certified mail with return receipt is the floor. You want to be able to prove what you sent and when it arrived.

The medical necessity letter is the lever

If you do one thing well at Level 2, do this one.

From what I have seen, the IRE's reviewers are clinicians making a coverage call on the same record the plan saw, plus whatever you add. The plan has already told them, in writing, why your service does not meet Medicare coverage criteria. Your physician's letter is the only document in the package that can credibly say “the plan is wrong, and here is the clinical reason why.”

A medical necessity letter that actually moves the needle, in my experience, does four things:

  • Establishes the clinical course. What is the diagnosis, when was it made, what has been tried, what happened. Two or three short paragraphs, not a novel.
  • States why the requested service meets Medicare coverage criteria. Name the criteria. If there is an NCD, cite it. If the plan applied MCG or InterQual, walk through how the patient's specific findings meet the cited criteria.
  • Rebuts the plan's denial reasoning point by point. If the plan said “patient has not failed conservative therapy,” the letter needs to list the conservative therapies tried, the dates, and the outcomes. Generic “the patient needs this” letters do not work because they do not engage the plan's actual argument.
  • Is signed by the treating physician on letterhead, with NPI and contact info, dated within the last 30 days.

If your physician's office hands you a one-paragraph “to whom it may concern” letter, push back. The letter is the case. A weak letter is the most common reason I see good clinical situations get upheld at Level 2.

What the reversal data actually shows

You will see two numbers in the wild and they get confused often.

The first is KFF's January 2026 analysis of 2024 CMS data: 80.7% of Medicare Advantage Level 1 appeals were fully or partially overturned. That is a real, sourced number, and it is high. Most denials that get appealed get reversed, often because the appeal forces the plan to actually look at the clinical record.

The second number, which you will see thrown around as something like “35% of IRE appeals are overturned,” I cannot find in any primary CMS source. KFF does not separately report a Level 2 reversal rate in the 2026 analysis. The actual CMS QIC decision data, looking at hundreds of thousands of Part C and Part D appeals processed since 2020, suggests Level 2 favorable rates are in the single digits, not the mid-30s. The “35%” number reads to me like AI-generated content that got copied across template sites.

I am being honest about this because I think it changes how you should approach Level 2. If Level 1 reversal is 80%+ and Level 2 reversal is in the single digits, the takeaway is not “give up at Level 2.” The takeaway is: the IRE is reviewing a record the plan curated against you, and most appellants are submitting nothing. The submissions that win at Level 2 are the ones where the enrollee or their advocate did the work to put a coherent supplemental package in front of the reviewer. The quality of what you send matters more here than at any other level.

If the IRE denies you too

If the IRE upholds the plan's denial, the case is not over. The next three levels are:

  • Level 3: Hearing before an Administrative Law Judge at OMHA. The 2026 amount in controversy threshold is $200 (Federal Register notice). You have 60 days from the IRE decision to request the hearing.
  • Level 4: Review by the Medicare Appeals Council. No dollar threshold. 60 days from the ALJ decision.
  • Level 5: Judicial review in federal district court. 2026 threshold is $1,960. 60 days from the Council decision.

Each level has its own request form, its own filing process, and its own decision timeline. I covered all five in the first post in this series, so I will not repeat it.

One specific note for post-acute care denials (SNF, home health, inpatient rehab): if you are caught in an Optum Home and Community Care decision (the Optum group formerly known as naviHealth, which still uses the nH Predict algorithm), the algorithmic-denial context I wrote about previously is worth reading. The Estate of Lokken v. UnitedHealth Group litigation is still active and the March 2026 discovery order has made some of the internal algorithm documentation discoverable.

If you would rather not do this yourself

The honest reality is that putting a usable Level 2 supplemental package together, on the timeline that matters, while also being a patient or a working adult child caring for a parent, is a lot. The physician's office has to be chased. Records have to be pulled. The denial letter has to be read closely enough to actually rebut. Certified mail has to go out. Then you wait, and then if it comes back denied, you do it again at Level 3.

DenyBack is the service I built for this. $39 flat, one fee, no subscription. We handle the full Medicare Advantage appeals workflow including the IRE supplemental submission, and we auto-escalate at Day 1, Day 14, Day 30, and Day 45 via Lob certified mail so nothing sits. If you want us to take this off your plate, denyback.com.

If you would rather run it yourself, that is also a fine call. Most of what you need is in this post. The part I would not skip, whoever is filing, is the medical necessity letter. That is the lever.