CJ Karrer
Writer · Reviewed by Richard ChanUpdated Jun 12, 2026
2 min read
Redetermination is the first level of the formal Medicare appeals process when a claim or service is denied.
You must file a request for redetermination within 120 days of receiving your Medicare Summary Notice (MSN) indicating the denial.
A Medicare Administrative Contractor (MAC) who was not involved in the original decision will conduct an independent review of your claim.
Redetermination, also known as an appeal, is a process that allows individuals to request a review and reconsideration of health insurance decisions made by their insurance plan or provider. This process is crucial in situations where a claim, coverage determination, or other healthcare-related decision is denied or not fully approved. Understanding the redetermination process empowers individuals to challenge unfavorable decisions and seek fair resolutions for their healthcare needs. In this article, we explore the concept of redetermination and how it can be utilized to advocate for appropriate health insurance coverage.
Redetermination is the formal process through which individuals can appeal health insurance decisions that they believe are incorrect or unjust. This process allows for a review of the initial decision by an independent entity or a panel of experts.
Individuals may consider requesting redetermination in the following situations:
The redetermination process typically involves the following steps:
If the redetermination process does not yield a satisfactory result, some states offer the option of an external review. External review involves an independent third party reviewing the appeal, and their decision is binding on the insurance plan.
Redetermination is a crucial process that allows individuals to challenge health insurance decisions that they believe are unjust or incorrect. It provides a mechanism for seeking fair resolutions for denied claims, coverage determinations, and prior authorization denials. Understanding the redetermination process and its role in advocating for appropriate health insurance coverage empowers individuals to navigate the appeals process effectively and secure the necessary healthcare services and treatments they need.