The $400 rule: patient-provider dispute resolution from the provider chair

When can a patient dispute your bill?

The federal patient-provider dispute process is open only to uninsured and self-pay patients, and only when your final bill runs at least $400 above the good-faith estimate you gave for a single provider. It is not a general complaint channel for insured patients, unhappy patients, or bills that merely feel high — the $400 gap over your written estimate is the sole trigger.

Three conditions must all be true: the patient is uninsured or self-pay (not billing insurance for the item), you provided a good-faith estimate in advance, and the billed charge exceeds that estimate by $400 or more for the same provider 1Ref 1Office of the Federal Register (2026).45 CFR Part 149 — Surprise Billing and Transparency Requirements.The operative rule text for the good-faith-estimate requirement and the patient-provider dispute resolution process, including the $400 threshold, the 120-day filing window, the SDR entity's role, and the collection-pause obligation.. The No Surprises Act built this dispute path specifically for people paying out of pocket, who have no insurer negotiating on their behalf 2Ref 2Centers for Medicare & Medicaid Services (2026).No Surprise Billing.That the No Surprises Act creates the patient-provider dispute process for uninsured and self-pay patients and separately restricts balance billing for insured patients in defined settings, distinguishing the two halves of the law.. If the patient is insured and running the charge through their plan, you are not in this process at all.

The 120-day clock and how a dispute starts

A patient has 120 calendar days from the date they receive the disputed bill to start the federal dispute — miss the window and the door closes. They file through the process HHS runs, pay a modest administrative fee set by the agency, and submit a copy of the bill alongside your good-faith estimate. You do not control the timing; the patient initiates, and you learn of it when HHS notifies you 1Ref 1Office of the Federal Register (2026).45 CFR Part 149 — Surprise Billing and Transparency Requirements.The operative rule text for the good-faith-estimate requirement and the patient-provider dispute resolution process, including the $400 threshold, the 120-day filing window, the SDR entity's role, and the collection-pause obligation..

• The clock runs from the bill, not the visit. The 120 days start the day the patient gets the charge, so a late-arriving bill extends the exposure window, not shortens it.
• The fee is the patient's, and small. HHS sets the administrative fee and updates it periodically; it is deliberately low so cost does not gate a legitimate dispute.
• You respond, you don't referee. When notified, you supply the estimate and any documentation the reviewer requests — you are a party to the dispute, not its judge.

Who decides, and what you must stop doing

Once a dispute is filed, a selected dispute resolution (SDR) entity — a neutral third party certified by HHS, not you and not the patient — reviews the estimate against the bill and decides the amount 1Ref 1Office of the Federal Register (2026).45 CFR Part 149 — Surprise Billing and Transparency Requirements.The operative rule text for the good-faith-estimate requirement and the patient-provider dispute resolution process, including the $400 threshold, the 120-day filing window, the SDR entity's role, and the collection-pause obligation.. You do not get to insist on your billed charge. While the review is pending you must not move the balance to collections, report it to a credit bureau, or take any retaliatory step against the patient for disputing, such as refusing future care 1Ref 1Office of the Federal Register (2026).45 CFR Part 149 — Surprise Billing and Transparency Requirements.The operative rule text for the good-faith-estimate requirement and the patient-provider dispute resolution process, including the $400 threshold, the 120-day filing window, the SDR entity's role, and the collection-pause obligation..

Treat the arrival of a dispute notice as an automatic hold on the account. The obligation to pause collection activity is not discretionary, and continuing to dun a patient whose dispute is live converts a billing disagreement into a compliance problem. If your practice policy would normally escalate an unpaid balance — the ordinary dismissal for nonpayment path — that escalation stops for the duration of the dispute.

What the reviewer can decide, and what it costs you

The reviewer works from two anchors: your billed charge and the good-faith estimate. If the disputed item was listed on your estimate, the most you can collect is the estimated amount; if it was not on the estimate at all, the reviewer sets a payable amount using the estimate as the benchmark 1Ref 1Office of the Federal Register (2026).45 CFR Part 149 — Surprise Billing and Transparency Requirements.The operative rule text for the good-faith-estimate requirement and the patient-provider dispute resolution process, including the $400 threshold, the 120-day filing window, the SDR entity's role, and the collection-pause obligation.. Once the SDR entity decides, that determination binds what you may collect for those services — you cannot re-bill the difference later.

The practical lesson is that the estimate caps your upside. A charge you never foresaw and never wrote down does not disappear, but it is decided against your own benchmark rather than your open-ended billed rate.

Your estimate is your best defense

Because the dispute turns entirely on the gap between your estimate and your bill, the good-faith estimate written at the front desk is what protects you later. Build it to reflect realistic charges — including the services you can reasonably foresee for the visit or course of care — and keep the signed copy in the record. Staying inside the $400 tolerance is not a number to game; it is the line between a routine bill and a federal review you did not choose.

• Foreseeable add-ons belong on the estimate. If a longer session, a no-show fee structure, or a likely follow-up is predictable, estimating it up front keeps the final bill inside the tolerance.
• Document the basis. A short note on how you built the figure turns "the bill is higher" into "here is why, and here is what I told you."
• Re-issue when the plan changes. If care escalates materially, a fresh estimate resets the benchmark honestly rather than leaving a stale one to be measured against.

How this differs from the insured balance-billing ban

The patient-provider dispute process is only one half of the No Surprises Act. The other half — the balance-billing ban — protects insured patients from surprise out-of-network charges in emergencies and at in-network facilities, and it runs through a completely different insurer-facing dispute track 2Ref 2Centers for Medicare & Medicaid Services (2026).No Surprise Billing.That the No Surprises Act creates the patient-provider dispute process for uninsured and self-pay patients and separately restricts balance billing for insured patients in defined settings, distinguishing the two halves of the law.. The $400 self-pay process and the insured ban do not overlap, and confusing them sends you down the wrong path.

If your disputing patient is actually insured and billing their plan, you are in balance billing territory, not the $400 self-pay dispute; the question of when balance billing is actually legal is answered on its own. Sort the patient's coverage status first — self-pay versus insured — because it decides which set of rules you are even operating under. The No Surprises Act for office practice governs both halves, but through separate machinery.