Emergency room billing is the process of submitting, adjudicating, and collecting payment for medical services delivered in an emergency department.
Every ER visit generates at least two separate claims — one from the facility for resources used and one from the physician for clinical services — and each follows different coding rules, different claim forms, and sometimes different payers.
That split is where most billing complexity begins. In this guide, we’ll be exploring:
- Where ER claims get denied and how to prevent it
- Which CPT codes emergency departments use most
- How facility billing differs from physician billing in the ED
- How the No Surprises Act changed out-of-network ER billing
- What EMTALA requires and how it affects the billing workflow
TLDR: What every ER billing team should know
Emergency department billing runs on two parallel tracks — and the financial risk changes depending on which one breaks.
- ER visits produce two claims — a facility claim (UB-04) for resources and a professional claim (CMS-1500) for physician services — each with its own coding and payment logic
- Emergency E/M codes 99281–99285 are assigned based on medical decision-making complexity under current CPT guidelines, not documentation volume
- The No Surprises Act (effective January 2022) prohibits balance billing patients for most emergency services from out-of-network providers, shifting payment disputes to the federal IDR process
- HHS-OIG identified over $15 million in improper Medicare payments for ED procedure codes billed with incorrect sites of service in a 2026 audit
- EMTALA requires Medicare-participating hospitals to screen and stabilize all emergency patients regardless of insurance — creating a billing obligation before eligibility is even confirmed
How does the ER billing workflow move from patient to payment?
Emergency department billing starts before a diagnosis exists.
Unlike scheduled visits, ER encounters produce charges in real time as clinicians order tests, administer medications, and perform procedures — often before insurance verification is complete.
Registration and triage
Basic demographics, insurance information, and chief complaint are captured at arrival. In many high-volume EDs, full insurance verification happens after treatment begins (or doesn’t happen until the claim is being built).
Clinical documentation
The treating physician documents the encounter — history, examination findings, medical decision-making, and procedures performed.
Under current CPT guidelines, E/M code selection for emergency visits depends primarily on medical decision-making complexity, not the length of the documentation.
Coding and charge capture
Medical coders assign CPT codes to physician services and facility revenue codes to resource utilization.
The facility and professional sides are coded independently, which is why a single ER visit can produce very different charges on each claim.
Claim submission
The facility submits a UB-04 claim. The physician group (or its billing service) submits a CMS-1500 claim. Both go to the patient’s insurer, but they’re adjudicated separately.
Payment and patient responsibility
The insurer pays according to the patient’s plan — applying deductibles, copays, and coinsurance. The patient receives an Explanation of Benefits (EOB) showing what was paid and what they owe.
See where your ER charges might be getting lost
Between facility fees, professional fees, and ancillary charges, ER billing has more moving pieces than most specialties. MedHeave’s revenue cycle team manages the full claim across each of them.
What is the difference between facility and physician ER billing?
This is arguably the most misunderstood part of emergency room billing, and most ER billing guides skip it entirely.
| Component | Facility billing | Physician billing |
| Claim form | UB-04 | CMS-1500 |
| What it covers | Nursing, supplies, equipment, room, labs, imaging | Clinical evaluation, procedures, medical decision-making |
| Coding basis | Revenue codes + facility E/M levels | CPT E/M codes (99281–99285) + procedure CPTs |
| Who bills | Hospital/facility | Physician group or emergency medicine practice |
| How level is determined | Resource utilization intensity | Medical decision-making complexity |
| Payment source | Facility’s contract with the payer | Physician group’s contract (may differ from facility) |
A patient with chest pain may receive a facility bill reflecting the monitoring equipment, cardiac enzymes, chest X-ray supplies, and nursing time — and a separate physician bill for the E/M evaluation, EKG interpretation, and clinical decision-making.
The two charges can look dramatically different, and that confusion is one of the most common patient complaints.
ACEP (American College of Emergency Physicians) guidelines confirm that facility-level ED billing should reflect the intensity of resources used — not the final diagnosis.
Which CPT codes are used in emergency department billing?
Emergency physicians rely heavily on E/M codes, supplemented by diagnostic and procedural CPTs depending on what the visit requires.
The five emergency department E/M codes, assigned by medical decision-making complexity:
- 99281 — straightforward MDM (minor problem, self-limited)
- 99282 — low-complexity MDM (two or more self-limited problems)
- 99283 — moderate-complexity MDM (one or more acute, uncomplicated problems)
- 99285 — highest-complexity MDM (life-threatening or severe functional impairment)
- 99284 — high-complexity MDM (one or more acute problems with systemic symptoms)
Common diagnostic and procedure CPTs billed alongside ER E/M codes:
| CPT code | Service |
| 93000 | 12-lead EKG with interpretation |
| 71046 | Chest X-ray, 2 views |
| 70450 | CT head without contrast |
| 36415 | Venipuncture |
| 96372 | Therapeutic injection (subcutaneous or intramuscular) |
| 12001–12007 | Simple wound repair |
| 31500 | Emergency intubation |
A 2025 study from Massachusetts General Hospital and Harvard Medical School found that the 2023 CPT documentation guideline changes significantly shifted ED billing distributions — with coding moving away from documentation volume and toward medical decision-making complexity (JACEP Open, 2025).
ED E/M CODE SELECTION
Medical Decision-Making Drives the Code Level
How did the No Surprises Act change ER billing?
Before January 2022, more than 25% of emergency department visits generated surprise out-of-network bills — where patients received care from providers outside their insurance network and were balance-billed for the difference.
The No Surprises Act changed three things for emergency room billing:
In-Network Cost Sharing
Patients pay only the same deductibles, copays, and coinsurance they would owe for an in-network emergency department visit.
No Balance Billing
Out-of-network emergency providers generally cannot bill patients for charges beyond their in-network cost-sharing responsibility.
IDR Resolves Payment
When providers and insurers disagree on reimbursement, the dispute is resolved through the federal Independent Dispute Resolution (IDR) process—not by billing the patient.
For emergency departments, this shifted the financial dispute from patient-to-provider to provider-to-insurer. The CMS patient protections page outlines the current rules.
The IDR volume has been enormous — CMS reports over 5.15 million disputes initiated since the system launched in April 2022, with emergency medicine among the highest-volume specialties.
What does EMTALA require and how does it affect billing?
EMTALA (Emergency Medical Treatment and Labor Act) requires any Medicare-participating hospital with an emergency department to provide a medical screening examination and stabilizing treatment to anyone who arrives, regardless of insurance status or ability to pay.
The billing implication is direct — EMTALA creates a treatment obligation before a payment source is confirmed. Hospitals must provide the screening and stabilization, then work out reimbursement afterward.
That sequence is why ER billing teams often deal with claims where eligibility wasn’t verified until after services were rendered.
EMTALA does not require hospitals to provide free care indefinitely. Once a patient is screened and stabilized, normal billing, transfer, and discharge protocols apply.
What are the most common ER claim denials?
Emergency department claims get denied more frequently than many other specialties because of the documentation speed, coding complexity, and payer variability involved.
The most common ER denial causes:
- Duplicate claim submission
- Timely filing deadline exceeded
- Modifier errors or missing modifiers
- Missing or incorrect diagnosis codes
- Incorrect E/M level relative to documentation
- Eligibility or coverage issues (patient’s insurance was inactive)
- Medical necessity not supported (payer determines ED-level care wasn’t required)
- Site-of-service coding errors (the 2026 HHS-OIG audit flagged $15 million+ in this category alone)
ER billing teams that separate denials into clinical denials (medical necessity, level of care) and technical denials (eligibility, coding, filing) can build targeted prevention workflows instead of treating every denial the same way.
Stop losing ER revenue to preventable denials
Emergency department billing requires speed, coding precision, and payer-specific workflows that most in-house teams struggle to maintain at scale.
MedHeave operates as a dedicated revenue cycle department for emergency medicine practices, managing the full claim lifecycle from charge capture through denial resolution.
- No Surprises Act compliance support and IDR documentation preparation
- Denial management with same-day rejection resubmission and root-cause tracking
- Performance-based pricing — MedHeave only gets paid when your practice gets paid
- First-pass claim rate of 90%+ and net collection rate of 97%+ across managed practices
- Dedicated emergency medicine billing teams familiar with E/M leveling, split billing, and payer-specific ED rules
Contact MedHeave to see how a structured billing team can recover the revenue your emergency department is leaving on the table.
Frequently asked questions
Here are questions emergency departments and billing teams ask most about ER billing.
Emergency room visits generate a facility bill and a physician bill because the hospital and the physician group operate as separate billing entities. The facility charges for resources — nursing, room, supplies, lab processing, imaging equipment. The physician charges for clinical evaluation and decision-making. Each submits its own claim on different forms (UB-04 and CMS-1500), and each may have a different contract with the patient’s insurer.
Under the No Surprises Act (effective January 2022), emergency departments generally cannot balance-bill patients for out-of-network charges. Patients pay their in-network cost-sharing amount, and payment disputes between the provider and insurer go through the federal Independent Dispute Resolution process. Some exceptions exist for post-stabilization services where the patient consented to out-of-network care in writing.
Observation services and emergency department E/M visits are billed differently and carry different reimbursement values. An ER E/M visit (99281–99285) covers the initial evaluation and treatment. Observation (99217–99220 or 99234–99236) covers extended monitoring typically lasting 8–48 hours. ACEP data shows observation services (CPT 99220 + 99217) can carry higher RVUs than a high-complexity ER visit (99285), making the classification decision financially significant.
EMTALA requires Medicare-participating hospitals to screen and stabilize anyone seeking emergency care, regardless of insurance status. Billing teams must be prepared to process claims where eligibility wasn’t verified before treatment. The law does not mandate free care — it mandates screening and stabilization. After stabilization, standard billing and collection processes apply, and hospitals may pursue reimbursement through insurance, patient responsibility, or charity care programs.
