Medicare Redetermination Form: Filing CMS-20027 for Part B Denials

The Medicare redetermination form is CMS-20027, the first-level appeal for a denied or underpaid Part B claim. File it with the Medicare Administrative Contractor (MAC) named on your remittance advice within 120 days of receiving the initial determination, and Medicare presumes you received that notice five days after its date. The MAC usually decides within 60 days, and no minimum dollar amount applies.

What is a Medicare redetermination? A redetermination is the first of five Original Medicare appeal levels: a written request that MAC staff who had no part in the original decision re-review a claim, filed on Form CMS-20027 or a letter containing the same required elements.

Undeny's Take

Before you open CMS-20027, ask whether the denial is appeal material at all. A transposed CPT code, a missing modifier, a wrong date of service or a claim denied as a duplicate is a clerical error, and CMS routes those to a reopening, which is the lighter-weight fix. The trap is that a reopening does not pause the 120-day redetermination clock, so if a reopening stalls, file the redetermination anyway before day 120. For true coverage or medical necessity denials, build the complete record now, not later. The QIC is the last level where you can add documentation freely; anything you hold back may be excluded at the hearing level. For outpatient therapy and other documentation-heavy services, that means the treatment notes for every denied date of service, plus the order or plan your notes refer to, in the first packet.

Reopening or Redetermination: Pick the Right Door

CMS is explicit that MACs "do not process claim corrections involving minor errors and omissions through the appeals process." The Medicare Claims Processing Manual, Chapter 34, defines clerical errors to include:

Mathematical or computational mistakes and misapplied fee schedules
Transposed procedure or diagnostic codes and inaccurate data entry
Incorrect data items such as provider number, modifier or date of service
Claims denied as duplicates that you believe were not duplicates

A party may request a reopening within 1 year of the initial determination for any reason. Part B MACs are required to offer telephone reopenings, and written requests are also allowed. Two limits matter. First, a reopening cannot add services you never billed. Second, "requesting a reopening does not toll the timeframe to request an appeal." If the denial is about coverage, documentation or medical necessity rather than a keying error, go straight to the redetermination.

Claims returned as unprocessable (missing or invalid data) are different again. The manual says such a claim "is not denied, and, as such, is not afforded appeal rights." Correct it and resubmit it as a new claim within the timely filing limit. Our CO-16 missing information guide covers the usual causes.

Filing the Medicare Redetermination Form With Your MAC

Confirm the denial carries appeal rights: it is not an unprocessable return and not a timely filing denial, which cannot be appealed.
Find the date on the remittance advice, add 5 days for presumed receipt, then add 120 days to get your filing deadline.
Download Form CMS-20027 (current version 01/20) from CMS, or prepare a letter with every required element.
Enter the beneficiary name, Medicare number, the item or service, the date of service, and the date of the initial determination notice, and attach a copy of that notice.
Check whether the appeal involves an overpayment, then explain in plain terms why the determination is wrong.
Attach all supporting evidence, or a statement of what you will send and when; evidence must arrive before the MAC decides.
Send the request to the MAC that issued the remittance advice, through its provider portal where offered or to the address it lists, and keep proof of the date sent.
Calendar the 60-day decision window and, if the denial is upheld, the 180-day reconsideration deadline.

Elements CMS requires in a written request

If you skip the form, your letter must still include the beneficiary name, Medicare number, the specific services or items, the specific dates of service, the name of the party or representative, and why you disagree. A redetermination "must be requested in writing." The MAC can dismiss a request that is filed late without good cause, filed by someone who is not a proper party, or filed by a representative who was not properly appointed.

Which MAC gets California Part B appeals

The appeal goes to the MAC that made the initial determination, shown on the remittance advice. For California, CMS lists Noridian Healthcare Solutions as the Jurisdiction E MAC that "processes FFS Medicare Part A and Part B claims for American Samoa, California, Guam, Hawaii, Nevada and Northern Mariana Islands." CMS notes that "most MACs allow electronic submission of appeals through their website," so check your MAC's portal before mailing paper.

Level 2: The QIC Reconsideration on CMS-20033

If the redetermination upholds the denial, you have 180 days from receipt of the redetermination decision (again presumed 5 days after the notice) to request a reconsideration from a Qualified Independent Contractor. The Medicare reconsideration form is CMS-20033, the Medicare Reconsideration Request Form (01/20), and it is the same Medicare Part B reconsideration form whether the claim went through Noridian or another MAC. Use it or a letter that adds the name of the contractor that made the redetermination and any documentation the notice said was missing. CMS currently lists C2C Innovative Solutions, Inc. for both Part B North and Part B South, and both offer an appeals portal. The QIC generally decides within 60 days.

This is the level where evidence discipline pays off. CMS warns that "any documentation not submitted at the reconsideration level may be excluded from consideration at subsequent levels of appeal unless good cause is shown." Treat the reconsideration packet as the final record.

Levels 3 to 5: ALJ Hearing, Appeals Council, Federal Court

Level	Who decides	Deadline (from receipt of prior decision)	2026 minimum amount in controversy
3	OMHA administrative law judge or attorney adjudicator	60 days	$200
4	Medicare Appeals Council (Departmental Appeals Board)	60 days	None
5	U.S. District Court	60 days	$1,960

There is no single Medicare appeal form: each level has its own. Level 3 requests use Form OMHA-100 and can be filed through the OMHA e-Appeal Portal; OMHA generally decides within 90 days of receiving the request. Level 4 uses Form DAB-101 or a written request. The amount in controversy is the charge for the disputed services minus Medicare payments and any deductible or coinsurance that can be collected, and CMS recalculates the thresholds every year.

Medicare Timely Filing Limit for Part B Claims

Original claims must reach the MAC "no later than 12 months, or 1 calendar year, after the date the services were furnished." On professional claims with span dates, the line-item From date controls, and a date of service of February 29 must be filed by February 28 of the following year. A late claim is denied, but that denial "does not constitute an initial determination," so it cannot be appealed through redetermination. See the CO-29 timely filing guide for proof-of-filing tactics.

Appeal Rights When You Are Non-Participating

CMS's appeals booklet notes that non-participating physicians and suppliers "have limited appeal rights." A patient can transfer appeal rights to a non-participating provider who would otherwise have none, using Form CMS-20031. If a party appoints a representative on Form CMS-1696, the appointment is valid for 1 year from the date both the party and the representative sign it.

Redetermination Mistakes That Forfeit Appeals

Counting 120 days from the date you opened the remittance instead of the notice date plus 5 days.
Filing a redetermination for a keying error, waiting 60 days, and getting told to request a reopening.
Assuming a pending reopening protects the appeal deadline. It does not.
Appealing an unprocessable claim instead of correcting and resubmitting it.
Sending a thin Level 1 packet and an even thinner Level 2 packet, then trying to add records at the ALJ level.
Sending the reconsideration to the MAC instead of the QIC named on the redetermination notice.
For medical necessity denials such as CO-50, arguing the diagnosis without the notes that show why the service was needed on that date.

Frequently Asked Questions

Where do I get the Medicare redetermination form?

The form is CMS-20027, Medicare Redetermination Request Form, available as a free PDF in the Downloads section of the CMS first-level appeal page. The current version is dated 01/20. You may also use any written request that contains the required elements.

How long do I have to file a Medicare redetermination?

You have 120 days from the date you receive the initial determination. Medicare presumes receipt 5 calendar days after the date on the notice unless there is evidence otherwise, so the practical deadline is 125 days from the notice date. Late requests need a good cause explanation.

What is the difference between a redetermination and a reconsideration?

A redetermination is Level 1 and is decided by the MAC that processed the claim. A reconsideration is Level 2 and is decided by an independent Qualified Independent Contractor using Form CMS-20033, filed within 180 days of receiving the redetermination decision.

Can I appeal a Medicare timely filing denial?

No. CMS states that a denial for filing after the 12-month limit is not an initial determination and is not subject to appeal. Your options are limited to the exceptions CMS allows in the claims processing manual, so prevention matters more than appeals here.

Is there a minimum dollar amount for a Part B appeal?

Not for the first two levels or for Medicare Appeals Council review. An ALJ hearing requires at least $200 in controversy in calendar year 2026, and federal court requires $1,960. CMS updates both figures every year.

Does requesting a reopening extend my appeal deadline?

No. Chapter 34 of the Medicare Claims Processing Manual says requesting a reopening does not toll the time to request an appeal. If the reopening is not resolved in time, file the redetermination before the 120-day window closes.

Informational only, not legal, medical, or billing advice. Verify against current CMS guidance and your MAC's instructions before filing.

Draft the Redetermination Narrative

Undeny turns the denial code into a structured appeal letter you can attach to CMS-20027 or send as the written request. Generate an appeal · Start a Medicare appeal · Join the waitlist