Before January 1, 2022, it was entirely legal for an out-of-network anesthesiologist to bill you thousands of dollars after a surgery at an in-network hospital — even though you never chose that provider and had no way to know they were out of network. The No Surprises Act made that illegal. But the law only covers specific situations, and understanding the boundaries matters when you are looking at a bill you did not expect.
What the law prohibits
The No Surprises Act bans balance billing — charging patients more than their in-network cost-sharing amount — in two categories of care:
- Emergency services at any facility. If you go to an emergency room or receive emergency care, providers cannot bill you more than your in-network cost-sharing even if the facility or the treating physician is out of network. This applies regardless of whether you chose the facility or were taken there by ambulance.
- Non-emergency services at an in-network facility where you had no meaningful choice of provider. The most common example: an out-of-network anesthesiologist, radiologist, or assistant surgeon is assigned to your care at an in-network hospital. You did not choose them and could not reasonably have chosen an alternative. The No Surprises Act covers these providers.
In both cases, your insurer pays the out-of-network provider at a rate negotiated through an independent dispute resolution process. Your responsibility is capped at your in-network cost-sharing. The provider cannot bill you for the rest.
Who is covered
The law applies to most private health insurance plans, including employer-sponsored plans (including self-insured plans), individual and family plans purchased through the marketplace, and student health plans. It does not apply to short-term health plans, health care sharing ministries, or retiree-only plans. Medicare and Medicaid have separate protections.
Uninsured and self-pay patients are covered by a related provision: providers must give you a written Good Faith Estimate of expected costs before any scheduled service. If your final bill exceeds that estimate by more than $400, you can dispute it through the federal Patient-Provider Dispute Resolution process.
The consent exception
This is the part most patients do not know. For non-emergency, scheduled care at an in-network facility, an out-of-network provider can opt out of the law's protections and bill you at out-of-network rates, but only if:
- They give you a written notice at least 72 hours before the service explaining that they are out of network and what the estimated cost will be
- You sign a consent form acknowledging you understand you will be billed at out-of-network rates and waiving your protections under the No Surprises Act
If you did not receive that written notice at least 72 hours in advance, and you did not sign a consent form, the provider cannot legally bill you more than your in-network cost-sharing. A bill that arrives without this prior consent process is a No Surprises Act violation.
What the consent notice must include
The written notice must state the provider is out of network, list the provider's estimated charge and your estimated out-of-pocket cost, include a list of in-network providers at the facility who could perform the service, and state that you can choose an in-network provider instead. A generic financial responsibility form is not sufficient. The notice must be service-specific and signed.
What the law does not cover
Knowing the exclusions is just as important as knowing the protections.
- Out-of-network facilities. If you choose to receive care at an out-of-network hospital or facility, the No Surprises Act generally does not apply. The protections are designed for situations where you received care at an in-network facility but were unknowingly treated by out-of-network providers within it.
- Ground ambulance services. Ambulance transport is explicitly excluded from the No Surprises Act. Several states have enacted their own ambulance balance billing protections, but there is no federal prohibition.
- Air ambulance from non-participating providers. Air ambulance from providers that do not participate in any insurance network is excluded, though the law does limit cost-sharing for air ambulance from participating providers.
- Dental and vision care. Stand-alone dental and vision plans are excluded.
How to dispute a bill that violates the No Surprises Act
If you receive a bill you believe violates the No Surprises Act, the dispute process is separate from a standard hospital bill dispute. Phone calls are ineffective here. Do this in writing.
First, gather your documentation: the bill itself, your explanation of benefits from your insurer, and any consent forms you were given before the procedure. If you were not given a consent form, note that explicitly.
Second, contact your insurer. Tell them you received a bill you believe violates the No Surprises Act and ask them to initiate the insurer-provider dispute resolution process. Insurers are required to handle these disputes directly with the provider. Your cost-sharing cannot exceed the in-network amount while the dispute is pending.
Third, file a federal complaint at CMS. The federal portal handles complaints against providers who violate the law. Violations can result in a civil monetary penalty of up to $10,000 per violation. CMS investigates complaints and can compel providers to refund excess charges.
Sample dispute language
"I received a bill for [service] on [date] from [provider name], an out-of-network provider, for services performed at [facility name], an in-network facility. I did not receive the required 72-hour written notice or sign a consent form waiving my No Surprises Act protections. Under 42 U.S.C. § 300gg-111, this charge is prohibited. I am requesting that you correct my balance to reflect my in-network cost-sharing only and confirm in writing that the remaining balance has been waived."
For the full dispute process from requesting an itemized bill through sending a formal letter and escalating if needed, see our step-by-step hospital bill dispute guide. Once you have sent a dispute letter, here is what to expect in the 30 days after.
State-level balance billing protections
Many states had their own balance billing laws before the federal law passed. Where state law provides stronger protections than the No Surprises Act, state law applies. Where federal law is stronger, federal law applies. The practical result is that patients in states with robust balance billing laws get the benefit of both.
States with notable balance billing protections include New York, California, Texas, Colorado, and Illinois. Your state insurance commissioner is the right contact for state-level violations. The NAIC maintains a directory of state insurance departments at naic.org.
How common are No Surprises Act violations
In the first two years after the law took effect, CMS received tens of thousands of complaints. A 2024 report from the Department of Health and Human Services found that surprise billing complaints were concentrated in emergency medicine, anesthesiology, radiology, and pathology — the specialties most likely to involve providers patients cannot choose in advance.
If you received emergency care or had surgery at an in-network facility and received a separate bill from a provider you did not recognize, it is worth checking whether that bill is permitted. Our guide to common billing errors covers the other patterns to look for on the same bill.