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Issue 14 · August 2026
Two clocks run on every denied claim, and most practices only know about one
Before you act on any number here: Practice Insider gives general operational guidance on running an independent practice. It is not legal, compliance, tax, or financial advice. Confirm any claim filing, appeal, reopening, overpayment, or Medicaid billing step with qualified healthcare counsel, a certified professional coder, or your own advisor before acting on it. Medicare appeal, reopening, and overpayment procedures are administered by your Medicare Administrative Contractor, and contractor instructions and coverage determinations vary by jurisdiction and change frequently, so verify current requirements and forms with your own MAC before filing anything.
The lead: the denial your billing desk should not be appealing
A denied Medicare claim usually gets one of two responses in a small practice. Someone files an appeal, or someone writes it off. There is a third path, and for one common category of denial it is the only path the contractor is allowed to take. Duplicate denials, inaccurate data entry, and mathematical or computational mistakes are clerical errors, and the rule requires a Medicare contractor to process a clerical error as a reopening rather than as a redetermination.
The two clocks are 120 calendar days and 1 year. A request for redetermination, the first level of appeal, must be filed within 120 calendar days from the date a party receives the notice of initial determination, and receipt is presumed to be 5 calendar days after the date of that notice. A party may request a reopening within 1 year from the date of the initial determination for any reason, and at any time when the determination was unfavorable and the purpose is to correct a clerical error it was based on.
The gap between those two clocks is where recoverable money sits. A denial that aged past 120 days is not automatically finished if the underlying problem was a duplicate flag or a transposed digit. A reopening request is a separate filing with its own deadline, and it does not require the appeal window to still be open.
What to check before you write anything off
Pull every Medicare denial your practice closed without payment over the last 12 months and sort it by denial reason. Duplicate denials and data-entry rejections are the two categories that most often belong in a reopening queue instead of a write-off queue. One limit to know going in: third party payer error does not count as clerical error under the rule, so a payer coverage or policy decision stays on the appeal track with its 120 day clock.
Quick hits
Filing: the 1 calendar year limit with almost no workflow exceptions
Medicare fee-for-service claims for services furnished on or after January 1, 2010 must be filed no later than the close of the period ending 1 calendar year after the date of service. The exceptions written into the rule are narrow, each carries its own set of conditions, and none of them cover a busy front desk: contractor error or misrepresentation, retroactive Medicare entitlement, retroactive disenrollment from a Medicare Advantage or PACE organization, and a state Medicaid recovery six months or more after the service. A claim sitting unbilled because a chart is unsigned or a credentialing file is still open is a claim with the clock running on it. A weekly report of held and unbilled encounters sorted by date of service is the cheapest control against that.
Overpayments: 60 days to return it, 6 years to have found it
An identified overpayment must be reported and returned by the later of 60 days after the date it was identified or the date any corresponding cost report is due. The lookback runs 6 years from the date the overpayment was received. The consequence of missing that deadline is what gives it teeth: an overpayment retained past the deadline becomes an obligation under the federal False Claims Act. A practice that finds a coding or units error going back a year or two will sometimes sit on it while deciding what to do about it. The 60 day clock starts at identification, not at the end of that deliberation.
Medicaid: the 12 month filing floor and the 30 day payment standard
Federal rules require a state Medicaid agency to make providers submit all claims no later than 12 months from the date of service, and a state is free to set a window shorter than that. The payment standard runs the other direction: the agency must pay 90 percent of clean claims from practitioners in individual or group practice within 30 days of receipt, and 99 percent within 90 days. A clean claim is one the agency can process without going back to you or to a third party for more information. If your Medicaid aging is stacked well past 30 days, the first number to establish is how many of those claims were clean on arrival, because that is the population the standard is measured against.
Putting this issue to work
Reopening requests, appeal deadlines, and overpayment returns all land on the same desk as daily claim submission, and that desk is usually the first one to fall behind when volume climbs. If the sections above describe your practice, the question to answer before your next renewal is whether denial work belongs in house at all. Compare medical billing and RCM services on GetPracticeHelp and filter by specialty and payer mix.
Compare billing services →On the numbers: the 1 calendar year Medicare filing limit and its exceptions are 42 CFR 424.44; the 120 calendar day redetermination window and the 5 day receipt presumption are 42 CFR 405.942(a); the reopening rules, including the clerical error category and the third party payer error carve-out, are 42 CFR 405.980; the 60 day return deadline and the 6 year lookback are 42 CFR 401.305; the Medicaid 12 month filing requirement and the 30 and 90 day clean-claim payment standards are 42 CFR 447.45(d). Contractor instructions, state Medicaid rules, and commercial payer contracts layer their own deadlines on top, and those are frequently shorter. Treat these as the federal floor to check your own payer mix against, not guarantees.