Emergency medicine coding audits are becoming a compliance concern for hospitals, emergency physicians, and billing teams. CMS, Medicare Ad. This is the reason emergency department claims are receiving closer review than before.
The most frequently audited areas are:
- High-level E/M services
- Critical care billing
- Modifier 25 usage
- Medical necessity documentation
Understanding why audits are increasing and what mistakes trigger audit findings is crucial in 2026. It can help protect revenue and keep your practice compliant.
Why Are Emergency Medicine Coding Audits Increasing in 2026?
OIG and CMS have expanded ER coding oversight due to:
- Documented patterns of upcoding
- Improper site-of-service billing
- Unsupported critical care claims in Medicare and Medicaid programs.
The OIG’s Work Plan now includes a dedicated audit examining Medicare payments for emergency department services billed in non-emergency settings. CMS identified a pattern: certain CPT and HCPCS codes carry a site-of-service requirement. The patient must actually be seen in an emergency department for these codes to apply.
RACs are also active. The CMS Recovery Audit Program flags overpayments through both automated and complex reviews. Complex reviews require qualified clinical staff to examine medical records directly. ER claims consistently appear on approved RAC review topic lists because E/M level selection errors and critical care documentation gaps generate systematic overpayments.
Three enforcement forces are converging on ER billing right now:
- OIG Work Plan audit of ER services billed in non-ER sites
- RAC complex reviews targeting E/M level upcoding (99284, 99285)
- MAC prepayment reviews for critical care codes 99291 and 99292
| KEY AUDIT TRIGGERS IN EMERGENCY MEDICINE – 2026 | |
| Audit Body | Primary Focus Area |
| OIG | Site-of-service mismatch for ER CPT codes |
| RAC | E/M level upcoding (99284/99285 patterns) |
| MAC | Critical care time documentation gaps |
| CMS CERT | Insufficient medical necessity documentation |
| UPIC | Modifier 25 misuse with same-day procedures |
What Are the Most Audited CPT Codes in Emergency Medicine?
The highest-risk codes in ER billing are:
- 99284
- 99285
- 99291
- 99292
They need to be well documented in either MDM or time. There are a lot of providers that don’t provide enough.
CPT codes 99281-99285 are used in the E/M visit of the emergency department. These codes are not time based, but are based mainly on Medical Decision Making (MDM). Time-based coding is not applicable to ED E/M codes (99281 – 99285), according to the ACEP and AMA. The time based codes are 99291 and 99292.
CPT 99285 is typically used for high-complexity cases involving a threat to life or bodily function. Moderate to high complexity is in code 99284. These two codes are the two most commonly used ED codes, and as such are the most closely reviewed by Medicare.
| EMERGENCY DEPARTMENT CPT CODES AT A GLANCE | |
| CPT Code | Complexity Level | MDM Required |
| 99281 | Minimal – Single self-limited problem, minimal MDM |
| 99282 | Low – Straightforward MDM, minor acute illness |
| 99283 | Moderate – Acute illness with systemic symptoms |
| 99284 | High – Requires intensive supervision, new/undiagnosed problem with uncertain prognosis |
| 99285 | High/Life-threatening – Poses threat to life or bodily function |
| 99291 | Critical Care – 30 to 74 minutes; time must be documented |
| 99292 | Critical Care add-on – Each additional 30 minutes beyond first 74 |
Documentation that indicates moderate complexity is consistently identified as 99285 claims by auditors. They also identify 99291 claims that do not document time separately, especially those for separately billable procedures such as intubation (CPT 31500) and central line insertion (CPT 36556) which are also billed on the same date. The procedure minutes will not count towards critical care time.
What Are the Most Common ER Coding Errors That Trigger Audits?
The majority of ER audits are based on a few basic coding and documentation errors. Early detection of these errors can help minimize audit findings, denials, and lost revenue.
1. Upcoding E/M Levels Without Documentation Support
This is the most frequent finding in an ER audit. A provider is seeing a patient for a moderate complexity visit and codes a CPT 99285. The auditors check the referenced MDM, the number of problems, the data reviewed, the risk of complications against the code which is being billed. If the MDM is under the threshold, the difference will be recovered and the claim is downgraded.
The fix is documentation-first coding.
2. Critical Care Time Errors (99291/99292)
Critical care codes require documented time. CPT 99291 covers 30 to 74 minutes of critical care. CPT 99292 covers each additional 30 minutes beyond that. The time counted must exclude time spent performing separately billable procedures.
Those providers who perform intubation, chest tube placement (CPT 32551), or CPR (CPT 92950) during the same encounter but do not subtract the procedural time from the critical care time are overbilling, even if unintentionally.
3. Modifier 25 Misuse
Modifier 25 will permit billing for a significant and separately identifiable E/M service on the same day as a procedure. The E/M service is clearly documented and is in addition to the procedure, not part of it and is clearly documented in CMS and the NCCI Policy Manual.
A frequent mistake is adding Modifier 25 to 99285 because the procedure was also done, and to not provide the separate evaluation that led to the E/M visit. Auditors search for the separate documentation of History, MDM, and Assessment from the procedure note.
4. Site-of-Service Billing Errors
ER CPT codes 99281–99285 are Type A emergency department codes. They need the facility to be open 24/7. For type B facilities, use codes G0380-G0384.
OIG’s current Work Plan includes a specific audit of Medicare payments made for ER codes billed in non-emergency settings. If a provider uses 99281–99285 at a facility that does not meet the Type A definition, the claim is improper by definition.
5. CPT-ICD-10 Misalignment
Each CPT code must have an ICD-10 diagnosis code that shows medical necessity. A red flag is to report only minor, self-limited conditions with a CPT 99285 code. Is it to use a nonspecific/unspecified diagnosis code when there is a more specific code available. Patterns are identified by auditors and claims are denied by payers.Payers reject claims, and auditors flag patterns.
| ER CODING AUDIT READINESS CHECKLIST | |
| Documentation Item | What Auditors Check |
| E/M MDM Level | Number of diagnoses, data reviewed, risk of complications/morbidity |
| Critical Care Time | Exact minutes documented; procedure time subtracted |
| Modifier 25 | Separate documentation for E/M beyond any same-day procedure |
| Facility Type | Type A (24/7 open) vs. Type B, correct code set used |
| ICD-10 Specificity | Diagnosis code supports medical necessity for billed CPT level |
| Provider Signature | Dated, legible, complete, meets CMS signature requirements |
| Procedure Unbundling | No separately-billed procedures bundled into E/M time |
How Do RAC Audits Work in Emergency Medicine?
RAC audits identify and recover Medicare overpayments through automated system-level reviews and complex reviews requiring medical record examination. ER providers receive Additional Documentation Requests (ADRs) when a claim triggers review.
The CMS Recovery Audit Program (RAC) uses two review methods. Automated reviews identify improper payments algorithmically, no medical records needed. Complex reviews require a qualified clinical reviewer to examine the actual documentation.
When a complex review is triggered, the RAC issues an Additional Documentation Request (ADR). Providers have 45 days to submit records. Missing the ADR deadline is the fastest path to an automatic denial. The deadline is firm, and the burden of proof rests with the provider.
ER practices are particularly vulnerable because high-volume, high-acuity coding patterns, like frequent 99285 billing, statistically trigger outlier flags. CMS uses statistical models to identify providers whose billing patterns deviate from peers in the same specialty and geography.
What Should ER Providers Fix Right Now to Reduce Audit Risk?
ER providers should conduct internal coding audits quarterly, focus documentation on MDM components, train physicians on time-based critical care requirements, and verify site-of-service classifications annually.
1. Audit Your Own Claims Before CMS Does
Pull a 90-day sample of your most frequently billed codes, especially 99284, 99285, 99291. Review MDM documentation against the billed level. If documentation does not support the code, the claim is at risk.
Quarterly internal audits catch systemic issues before they grow into RAC patterns. Certified coders (CPC, COC) should lead this review.
2. Fix Critical Care Documentation Templates
Add a time-stamp field to every critical care encounter. Require providers to document: total time spent on critical care services, start and end times, and any procedures excluded from that time count.
Without explicit time documentation, a 99291 claim will fail under complex review, regardless of how sick the patient actually was.
3. Train Physicians on MDM, Not Just Codes
Physicians drive documentation quality. They need to understand the three MDM components CMS uses to justify E/M levels: number and complexity of problems, amount and complexity of data reviewed, and risk of complications or morbidity.
When physicians understand what auditors look for, documentation improves naturally. Brief quarterly coding updates, 20 minutes at a department meeting, make a measurable difference.
4. Verify Your Facility’s Site-of-Service Classification
Confirm annually that your facility qualifies as a Type A emergency department under Medicare rules. If your hospital’s ER hours or staffing have changed, your site-of-service code designation may need updating. Billing 99281–99285 at a Type B facility is an audit-ready error.
5. Work With a Compliant Billing Partner
Outsourcing ER billing to a compliant revenue cycle team adds a layer of protection. A qualified billing partner reviews claims before submission, monitors denial patterns, and responds to ADRs on your behalf. Kansas Medical Billing provides emergency medicine billing support built around CMS and OIG compliance standards.
What Are the Penalties for ER Coding Violations?
In extreme cases, coding errors in emergency medicine can lead to rulings for the repayment of funds, civil monetary penalties pursuant to the False Claims Act, and exclusion from Medicare and Medicaid programs.
The penalties follow a tiered structure. RAC findings result in overpayment recoupment, the difference between what was billed and what was appropriate. CMS can offset future payments automatically if the provider does not repay within the specified window.
Under the FCA’s regulations civil penalties can be as high as $13,000 to $27,000 for every false claim made, and three times the amount of the overpayment.
At the most serious level, providers can face exclusion from federal healthcare programs. Exclusion means no Medicare or Medicaid reimbursement, effectively ending practice for most ER physicians.
The goal is never to reach that level. Proactive compliance, internal audits, documentation improvement, accurate code selection, keeps ER practices out of OIG’s crosshairs.
Is Your ER Practice Audit-Ready?
Kansas Medical Billing provides emergency medicine billing and compliance services built around CMS and OIG standards. We help ER providers catch documentation gaps before auditors do.
Contact Kansas Medical Billing to schedule a complimentary billing audit review.
Frequently Asked Questions
1. Can ER providers bill time-based E/M codes?
No. CPT states explicitly that time is not a descriptive component for ED E/M codes 99281–99285. MDM governs code selection for ED visits. Time only applies to critical care codes 99291 and 99292.
2. What happens if our practice gets an ADR from a RAC?
Respond within 45 days and provide the complete medical records that support the claim you are billing. Missing the deadline results in automatic denial. Consider designating a compliance coordinator to manage ADR responses.
3. How often should we conduct internal coding audits?
Quarterly is the minimum recommended frequency. Some high-volume ER practices audit monthly.
