Glossary · Billing
Redetermination (Medicare appeal level 1)
A redetermination is the first of five Medicare appeal levels, in which a Medicare Administrative Contractor (MAC) conducts a fresh review of a denied or partially paid claim; the request must be filed within 120 days of receiving the initial determination notice.
Verified May 8, 2026 · 5 sources ↓
Definition
Source · Editorial summary grounded in 5 cited references ↓
When a MAC issues an unfavorable coverage or payment decision on a Medicare Part A or Part B claim, the provider, supplier, or beneficiary may request a redetermination—a complete re-examination of the claim by a different MAC reviewer who was not involved in the original determination. This is Level 1 of the five-tier Medicare appeals process, which escalates through Qualified Independent Contractor (QIC) reconsideration (Level 2), Administrative Law Judge (ALJ) hearing (Level 3), Medicare Appeals Council review (Level 4), and federal district court review (Level 5).
The request is submitted using CMS Form 20027 (Medicare Redetermination Request Form) and must be received by the MAC no later than 120 calendar days from the date on the initial determination notice (Medicare Summary Notice or Remittance Advice). All supporting medical documentation—operative notes, imaging reports, physician orders, and any applicable ABN—should accompany the request, because the MAC will adjudicate the redetermination based solely on the record submitted; it will not routinely solicit missing records. The MAC is required to issue a decision within 60 days of receiving the request.
For orthopedic practices, redeterminations most commonly arise after denials tied to medical-necessity criteria in a Local Coverage Determination (LCD) or National Coverage Determination (NCD), post-payment audit adjustments, NCCI edit rejections, or modifier disputes. If the redetermination is unfavorable, the provider has 180 days to escalate to Level 2 reconsideration before a QIC.
Why it matters
Missing the 120-day filing deadline forfeits the right to redetermination entirely—there is no cure absent a documented extraordinary circumstance—so a single calendaring error can result in a permanent write-off of the denied amount. Equally consequential: submitting an incomplete medical record at Level 1 weakens all subsequent appeal levels, because the five-level process is generally additive, not corrective; reviewers at higher levels scrutinize whether the clinical evidence was present and legible from the start. For high-value orthopedic procedures such as total joint arthroplasty or complex spinal fusion, even a single unresolved redetermination can represent tens of thousands of dollars in unrealized reimbursement.
Common mistakes
Where people most often go wrong with this concept.
Source · Editorial brief grounded in cited references ↓
- Filing against the wrong entity—redeterminations go to the MAC that processed the original claim, not to CMS directly or to a QIC.
- Submitting the redetermination after the 120-day window without attaching a written explanation of good cause for the late filing, causing automatic dismissal.
- Omitting the date of the initial determination notice on Form CMS-20027, which can delay acceptance and restart the MAC's 60-day clock.
- Sending only the claim form (UB-04 or CMS-1500) without the underlying medical record, leaving the MAC no clinical basis to reverse the denial.
- Failing to include a copy of the ABN when the denial involves a claim the beneficiary was notified about in advance—its absence undermines arguments about patient liability and medical necessity.
- Confusing redetermination with a reopening: a reopening corrects clerical or minor errors within 12 months and is not an appeal; redetermination is the appropriate pathway when disputing a coverage or medical-necessity denial.
- Conflating Level 1 (redetermination by the MAC) with Level 2 (reconsideration by a QIC) and mailing the request to the wrong reviewer, wasting days and risking deadline expiration.
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01Who can file a redetermination request?
02How long does the MAC have to decide a redetermination?
03What is the deadline to file a redetermination?
04Is there a minimum dollar amount required to request a redetermination?
05What happens if the redetermination is also unfavorable?
06Can new evidence be submitted at the redetermination stage?
07How is a redetermination different from a claim reopening?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01cms.govhttps://www.cms.gov/medicare/appeals-grievances/fee-for-service/first-level-appeal-redetermination-medicare-contractor
- 02cms.govhttps://www.cms.gov/medicare/cms-forms/cms-forms/downloads/cms20027.pdf
- 03medicare.govhttps://www.medicare.gov/basics/forms-publications-mailings/forms/appeals
- 04medicare.fcso.comhttps://medicare.fcso.com/appeals/appeal-tips-documentation-include-your-part-redetermination-request
- 05cob.cms.hhs.govhttps://www.cob.cms.hhs.gov/MSPRP/help/msprp/case/verifyRedetermination.htm
Mira AI Scribe
Mira appeal-support note: If this encounter's claim is denied by the MAC and a redetermination is warranted, confirm the following before generating the appeal package—(1) the initial determination date is captured and falls within the 120-day filing window; (2) all clinical documentation referenced in the note (operative report, imaging interpretation, physician attestation of medical necessity, and any ABN) is attached and each page is legible, dated, and patient-identified; (3) the denial reason code from the Remittance Advice is mapped to the applicable LCD or NCD policy so the appeal letter directly addresses the specific coverage criterion at issue; (4) Form CMS-20027 is completed with the MAC name, claim number, and service date. Flag any procedure where the denial reason references an NCCI edit or modifier conflict—those require a separate modifier-dispute argument embedded in the redetermination letter rather than a pure medical-necessity argument. Do not route this request to a QIC; the redetermination goes to the MAC. Set a follow-up task 65 days out to confirm the MAC issued its decision within the required 60-day window.
See Mira's approachRelated terms
Reconsideration is the second of five Medicare appeal levels, in which a Qualified Independent Contractor (QIC)—entirely separate from the MAC that issued the original denial—conducts an independent review of the full administrative record and renders a new decision. It must be requested within 180 days of receiving the redetermination notice.
A Medicare Administrative Contractor (MAC) is a private insurance company under contract with CMS to process and pay Medicare Part A and Part B fee-for-service claims within an assigned geographic jurisdiction. MACs are the primary point of contact for providers on coverage policies, claims adjudication, and local coverage determinations.
A Local Coverage Determination (LCD) is a regional Medicare policy issued by a Medicare Administrative Contractor (MAC) that defines when a specific service, procedure, or supply is considered reasonable and medically necessary within that contractor's jurisdiction.
A National Coverage Determination (NCD) is a formal, evidence-based ruling issued by CMS that establishes whether Medicare will cover a specific item or service across all Medicare contractors nationwide. NCDs are binding on every Medicare Administrative Contractor and supersede any conflicting local policy.
An Advance Beneficiary Notice of Noncoverage (ABN) is a written notice providers and suppliers must deliver to Original Medicare (Part B) beneficiaries before furnishing an item or service that Medicare is expected to deny, transferring potential financial liability to the patient when properly executed.