A Medicare overpayment demand letter is not a routine bill. It opens a debt collection process with fixed deadlines, and the choices a physician makes in the first 30 days determine whether Medicare starts withholding money from future claims payments. The letter states an overpayment amount, explains how the Medicare Administrative Contractor (MAC) calculated it, and starts several clocks at once: a 15-day rebuttal window, a 30-day window to stop recoupment, and interest that begins accruing on day 31. Reading the letter correctly, and calendaring every deadline inside it, is the difference between a manageable repayment and an extrapolated demand that recoups from every claim submitted going forward.
What the Demand Letter Actually Says
Every demand letter a Medicare Administrative Contractor sends contains the same required elements: a statement that an overpayment occurred, the method used to calculate it, the patient name and Medicare Beneficiary Identifier for each claim at issue, the dates and types of services involved, the interest rate that applies if the balance is not paid within 30 days, and the recoupment process the MAC will follow if the physician does nothing. The letter also describes an extended repayment schedule for practices that cannot pay the balance at once, and it states the physician's rebuttal and appeal rights. None of these sections is boilerplate. The overpayment calculation section is where an extrapolated demand reveals itself, and the appeal rights section, not the cover page, is where the physician's actual deadlines live. The audit program behind the letter matters as much as the amount: a Recovery Audit Contractor (RAC) audit, a Unified Program Integrity Contractor audit, and a denial tied to a Local Coverage Determination each produce a differently structured calculation, and the redetermination response should match it.
The Sample Behind the Number
When a demand letter covers more than a handful of claims, the total is rarely a straight sum of the claims reviewed. Under Section 1893(f)(3) of the Social Security Act, a Medicare contractor may use statistical extrapolation to project a sample's error rate across an entire claims universe, but only if the contractor finds a sustained or high level of payment error, or if documented educational intervention already failed to correct the error pattern. That underlying determination is not itself reviewable on appeal, but the sample size, the claims universe it was drawn from, and the statistical formula used to calculate the projected overpayment are all reviewable, and they are frequently where an extrapolated demand collapses. A demand letter built on extrapolation should identify the sample size and the review period. If it does not, that gap belongs in the redetermination request.
The Deadlines That Actually Matter
The demand letter's calendar starts on the date it is issued, not the date it is opened. A rebuttal explaining why the MAC should not recoup the payment is due within 15 calendar days, though a rebuttal does not stop recoupment on its own. To prevent recoupment from starting, a redetermination request must be filed within 30 days of the demand letter. File after day 30 but before day 120, and recoupment will still stop once the MAC validates the appeal, but any amount already recouped will not be refunded until the case is decided. Interest begins accruing on day 31 regardless of whether an appeal has been filed, and absent an accepted redetermination request, standard recoupment against future Medicare payments begins on day 41. The outer deadline to file a redetermination at all, on any overpayment, is 120 days from the demand letter.
The deadline that controls recoupment is day 30, not day 120: miss it, and Medicare can begin withholding future claims payments before the appeal is ever decided.
Why Early Legal Counsel Is Critical
It is critical that physicians promptly retain experienced healthcare defense counsel upon receiving a Medicare overpayment demand letter, audit notice, or other government inquiry. Early legal intervention can protect the physician's rights, ensure the redetermination request is filed inside the window that actually stops recoupment, preserve challenges to the extrapolation methodology before they are waived, and allow counsel to communicate with the Medicare Administrative Contractor on the physician's behalf. Delaying legal representation past day 30 can significantly affect the outcome of a matter and expose the practice to recoupment it could otherwise have avoided.
How Health Law Alliance Can Help
Health Law Alliance represents physicians and practices nationwide in Medicare audit defense, including demand letter review, extrapolation challenges, and redetermination and reconsideration appeals. If your practice has received a Medicare overpayment demand letter, contact us today for a free consultation.
