What is the No Surprises Act, and when does it protect you?

The No Surprises Act is the most important federal medical billing law of the last 20 years. It went into effect on January 1, 2022, and if you've ever received an unexpected bill from an out-of-network anesthesiologist, ER doctor, or air ambulance, it almost certainly applies to your situation.

This guide walks through what the law actually does, when it kicks in, and how to use it if a hospital tries to bill you for charges it isn't allowed to.

What it does, in one paragraph

When you receive emergency care, OR non-emergency care at an in-network facility, out-of-network providers cannot bill you any more than your in-network cost-sharing amount. They have to negotiate with your insurance directly — they can't come to you for the difference. This is called the prohibition on "balance billing" by out-of-network providers in protected situations. It's codified at 45 CFR § 149.410.

The three situations where it applies

The law protects you in three specific contexts. Outside these, regular billing rules apply.

1. Emergency services at any facility

If you go to any hospital emergency room — in-network or not — and get treated for an emergency condition, you can only be billed at your in-network rate. This covers everything from the initial triage through stabilization, including services from out-of-network doctors who happen to be on shift that night.

The relevant section is 45 CFR § 149.110. It covers ambulance services from a ground ambulance too (though as of 2026, ground ambulance is still being phased in via a separate advisory committee process — the No Surprises Act protections are uneven for ground ambulance specifically).

2. Non-emergency care at an in-network facility, by an out-of-network provider

You schedule a surgery at a hospital that's in your plan's network. The hospital is in-network. But the anesthesiologist who shows up that morning is out-of-network. Or the pathologist who reads your biopsy is out-of-network. Or the radiologist who interprets your imaging is out-of-network.

You didn't choose those people. You couldn't have. And under 45 CFR § 149.410, they cannot balance-bill you. They must accept the in-network rate from your insurance.

This applies to ancillary services specifically: anesthesiology, pathology, radiology, neonatology, assistant surgeons, hospitalists, intensivists, and emergency medicine. It also applies to any service where you couldn't reasonably have known the provider was out-of-network in advance.

3. Air ambulance

Out-of-network air ambulance providers cannot balance-bill patients. Period. This is one of the cleanest protections in the law because air ambulance bills have historically run into the tens of thousands of dollars and patients had no control over which company showed up.

What "you can't be balance-billed" actually means on the bill

Here's the practical mechanics. After your visit:

1. The out-of-network provider sends a bill to your insurance.
2. Your insurance pays whatever it would have paid an in-network provider for the same service (this is called the "qualifying payment amount").
3. The provider can dispute that amount with your insurance via the federal Independent Dispute Resolution (IDR) process. They argue it out. You're not involved.
4. You owe only what you would have owed if the provider had been in-network — your normal copay, coinsurance, or deductible.

If you get a bill from the provider asking for the difference between what insurance paid and their full charge, that bill is illegal under federal law.

How to tell if you've been illegally billed

Pull out the bill and the corresponding Explanation of Benefits (EOB) from your insurance.

Look at:

• Who is the provider? Was the facility in-network? Was the provider in-network at the time of service?
• What does the EOB show for "patient responsibility"? This is the dollar amount your insurance has determined you owe.
• What is the provider billing you? Compare against patient responsibility.

If the provider is billing you more than your patient responsibility, AND one of the three conditions above applies (emergency, ancillary service at an in-network facility, or air ambulance), you've been illegally balance-billed.

What to do when you spot one

Three steps, in order.

1. Contact the provider's billing department in writing. State that you believe this is a balance billing violation under the No Surprises Act (45 CFR § 149.410 or § 149.110, depending on the situation). Request immediate withdrawal of the charge. Include the relevant dates and dollar amounts.

2. Contact your insurance company. They have to process the claim correctly under the law. Ask them to send the provider the qualifying payment amount and to inform the provider that the patient cannot be billed for the difference.

3. File a federal complaint if neither responds. The CMS No Surprises Help Desk takes complaints at cms.gov/nosurprises/consumers or by phone at 1-800-985-3059. They will investigate.

The provider can be fined up to $10,000 per violation for illegal balance billing under 42 U.S. Code § 300gg-131.

State laws sometimes go further

The federal No Surprises Act is the floor. Many states have stronger protections that apply on top:

• California (AB 72) extends balance-billing protection to non-emergency care at out-of-network facilities in some cases.
• New York has had surprise billing protection since 2015 and covers more situations than federal law.
• Texas (SB 1264) has aggressive anti-balance-billing rules with mandatory arbitration.
• Virginia (Code § 38.2-3445) has its own balance-billing protections for in-network facility ancillary services.

If you live in one of these states, your protections may be broader than what the federal law alone provides. Always check both.

What the law does NOT cover

There are situations the No Surprises Act explicitly does not protect:

• You went out-of-network voluntarily for non-emergency care. Standard out-of-network rules apply.
• You signed a waiver. Some non-ancillary providers can ask you to waive your No Surprises Act protections in writing 72+ hours before scheduled care. Don't sign these unless you have a good reason — they specifically forfeit your protection.
• Ground ambulance is partially excluded as of early 2026 (this may change as the regulations evolve).
• Self-pay scenarios — if you don't have insurance, different rules apply (you're entitled to a Good Faith Estimate under a different provision).

How Audra helps with No Surprises Act violations

When you upload a bill to Audra, we explicitly check every charge against the No Surprises Act. We look at whether the facility is in-network, whether the providers were also in-network, whether the service category falls under the ancillary protections, and whether the patient responsibility on the EOB matches what the provider is billing.

If we find a violation, we draft an appeal letter that cites the specific CFR section being violated and demands immediate withdrawal of the charge. We've seen audits surface NSA violations worth $1,500-$4,000 in single bills.

If you suspect you've been balance-billed and want to know for sure, run your bill through us. Your first audit is free, and we'll tell you in 60 seconds whether the No Surprises Act protections were honored.