Introduction
Emergency departments face unique billing challenges that often lead to insurance claim denials. These denials not only slow down the revenue cycle but also put financial pressure on emergency care providers.Unlike other medical settings, EDs must treat patients immediately—regardless of whether they have insurance or the ability to pay. Many times, insurance information is incomplete or unavailable at the time of service, and treatment can’t be delayed due to the critical nature of the cases.
As a result, emergency departments experience denial rates as high as 15–20%, much higher than the industry average of 5–10%. For high-volume EDs, these denials can translate into substantial revenue losses every year.In this article, we’ll look at the 10 most common denial codes that impact emergency medicine. We’ll explain what causes them and share actionable steps to help your department reduce avoidable denials and improve reimbursement—while continuing to deliver urgent care to those who need it most.
Common Denial Codes in Emergency Medicine
| Denial Code | Description |
|---|---|
CO-50 | Non-Covered Services |
CO-16 | Missing Information |
CO-18 | Duplicate claim/service |
CO-22 | Coordination of Benefits Error |
CO-29 | Late Filing |
CO-96 | Non-covered charges |
CO-109 | Claim Not Covered by Payer/Contracted Provider |
CO-140 | Patient/Insured Health Identification Number Missing/Invalid |
CO-197 | Precertification/Authorization Required |
CO-B7 | Provider Not Certified/Eligible |
Detailed Analysis of Top 10 Denials
1. Denial Code: CO-50
Description: Non-Covered Services
Non-covered service denials happen when an insurance plan doesn’t include coverage for the care provided. In emergency medicine, this often stems from the insurer deciding after the factthat the visit wasn’t a true emergency.These denials are especially difficult for emergency departments. Under EMTALA, they must assess and stabilize every patient, no matter their insurance status or ability to pay. There’s no room to delay care based on how an insurer might later classify the visit.Payers often issue these denials for cases they consider low-acuity conditions they believe could have been handled in a clinic or urgent care setting. This puts emergency providers in a tough position: they must act fast to treat patients, but risk losing payment for doing so.
Prevention:
- Implement robust clinical documentation practices that clearly articulate the presenting symptoms warranting emergency evaluation
- Document the patient’s condition from their perspective at presentation, not just the final diagnosis
- Educate providers on the importance of documenting decision-making factors that led to ED care
- Consider using a standardized emergency severity index (ESI) and document it prominently
- Develop standard documentation templates that capture typical emergency presentations
2. Denial Code: CO-16
Description: Missing Information
Denials for missing information happen when a claim can’t be processed due to incomplete or incorrect details. In emergency medicine, these are common because patient intake often happens under urgent, high-pressure conditions.It’s not unusual for registration teams to have limited time to gather full demographic data or insurance information. Errors like incorrect codes, missing policy numbers, or lack of physician documentation can easily lead to claims being rejected.These are known as technical denials, and they highlight the difficulty of balancing accurate billing with the need to provide immediate care.
Prevention:
- Implement real-time claim scrubbing technology to identify missing elements before submission
- Create emergency-specific registration protocols that prioritize essential information
- Establish follow-up processes to complete registration information post-stabilization
- Train registration staff on critical insurance verification information needed for claim submission
- Implement a quality review process for ED claims before submission
3. Denial Code: CO-18
Description: Duplicate Claim or Service
Duplicate claim denials can happen when a healthcare service appears to have been charged more than once. In emergency medicine, this issue is common because care often involves several providers, departments, or procedures within one visit. The fast-paced and overlapping nature of emergency care can make documentation complex. Additionally, if a claim is initially denied for another reason and later resubmitted without being clearly identified as a corrected claim, it may be mistakenly treated as a duplicate by the payer.
Prevention:
- Implement a robust claim tracking system to monitor submission status
- Create clear protocols for resubmitting denied claims versus submitting corrected claims
- Use appropriate modifiers to indicate distinct procedures performed during the same encounter
- Coordinate billing between hospital and physician groups to prevent overlapping claims
- Train staff to check claim status before resubmitting
- Utilize claim scrubbing software with duplicate detection capabilities
4. Denial Code: CO-22
Description: Coordination of Benefits Error
This denial occurs when there’s uncertainty about which insurance plan should pay first for a patient who has more than one type of coverage. In emergency departments, this can be especially challenging because patients often arrive without providing full insurance details. As a result, it can be hard to determine the correct order of billing. These types of denials are frequently seen in cases where patients are covered by both Medicare and private insurance, children are insured under policies from both parents, or individuals have both workers’ compensation and standard health insurance.
Prevention:
- Implement insurance verification systems that identify multiple coverage sources
- Train registration staff to ask specific questions about additional insurance coverage
- Create a follow-up process to verify coverage details post-emergency treatment
- Develop relationships with major insurers for expedited COB resolution
- Establish clear documentation procedures for accident cases that might involve auto insurance or worker’s compensation
5. Denial Code: CO-29
Description: Late Filing
Late filing denials arise when claims are sent to the insurance company after the deadline set by the payer, which can vary from 30 days to up to a year. In emergency medicine, meeting these deadlines can be difficult due to challenges like incomplete patient information at the time of service, delays in communication between hospital and physician billing teams, and the large number of claims being processed. These denials are especially frustrating because they often lead to a total loss of reimbursement, even when the care provided was essential and would have been covered if submitted on time.
Prevention:
- Create a comprehensive filing deadline calendar organized by payer
- Implement electronic claims submission for faster processing
- Establish a standard claim submission schedule (daily preferred for emergency claims)
- Prioritize claims approaching filing deadlines
- Track claim status regularly to identify and address issues promptly
- Document proof of timely filing for all claims (electronic confirmation receipts)
6. Denial Code: CO-96
Description: Non-covered Charges
Non-covered charges denials (CO-96) occur when certain services or items on a claim are not included in the patient’s insurance benefits. While similar to CO-50 denials, CO-96 focuses on specific line items rather than the entire claim. In emergency medicine, these denials often relate to treatments, medications, diagnostic tests, or levels of care that the insurer considers unnecessary or outside the scope of coverage. Examples might include drugs given in the ER, routine screenings done during the evaluation, or procedures labeled as “experimental” by the payer.
Prevention:
- Develop and maintain a database of commonly non-covered items by payer
- Train providers on insurance coverage limitations for high-cost medications or supplies
- Document medical necessity thoroughly for potentially non-covered items
- Implement claim scrubbing edits to flag potentially non-covered services before submission
- Review denied claims to identify patterns of non-covered charges by payer
- Consider alternative coding options when appropriate
7. Denial Code: CO-109
Description: Claim Not Covered by Payer/Contracted Provider
Out-of-network denials happen when a patient receives care from a provider or facility that isn’t part of their insurance plan’s network. In emergency settings, this is a common issue because patients often don’t have the ability—or time—to choose in-network care during a medical crisis. While laws like the Emergency Medical Treatment and Labor Act (EMTALA) and the No Surprises Act offer some level of protection, these denials still frequently occur. This is especially true when physicians working in a hospital are contracted separately and aren’t in the same insurance network as the hospital itself.
Prevention:
- Stay informed about the No Surprises Act requirements and implementation
- Maintain accurate provider directories with all contracted payers
- Develop clear financial policies for out-of-network patients
- Establish protocols for informing patients about network limitations when appropriate
- Create processes to identify potential network issues during registration
- Train staff on patient protection regulations related to emergency services
8. Denial Code: CO-140
Description: Patient/Insured Health Identification Number Missing/Invalid
Invalid or missing insurance ID denials occur when the insurance policy number on a claim is incorrect, incomplete, or not found in the payer’s system. In emergency departments, these issues are common because patients may be unable to communicate due to their condition, might not have their insurance card with them, or could provide outdated or inaccurate details. In many cases, treatment begins before full registration is possible—especially with unconscious or critically ill patients—which increases the risk of insurance identification errors on the claim.
Prevention:
- Implement real-time eligibility verification systems
- Train registration staff on insurance card data capture techniques
- Utilize technology to scan insurance cards when available
- Develop relationships with major local insurers for expedited verification
- Create follow-up processes to complete or correct insurance information post-treatment
- Implement quality checks before claim submission focusing on ID number verification
9. Denial Code: CO-197
Description: Precertification/Authorization Required
Prior authorization denials happen when a service that required advance approval from the insurance company was performed without that authorization in place. Although emergency screening and stabilization are typically exempt from prior authorization under EMTALA regulations, some services like hospital admissions, specific procedures, or care provided after the patient is stabilized may still need it. Emergency departments often struggle with this due to the urgent, unpredictable nature of emergencies and the fact that payer authorization departments may not be available around the clock to provide timely approvals.
Prevention:
- Understand federal and state regulations regarding emergency services and authorization requirements
- Create clear guidelines for clinical staff about which services might require authorization post-stabilization
- Develop relationships with payer authorization departments, including after-hours contacts
- Implement an authorization tracking system integrated with the ED workflow
- Train staff on payer-specific authorization requirements and timeframes
- Document all authorization attempts, including call reference numbers
10. Denial Code: CO-B7
Description: Provider Not Certified/Eligible
This denial arise when a claim is submitted under a provider who isn’t enrolled, credentialed, or recognized by the patient’s insurance plan. In emergency departments, this is a common issue due to the diverse mix of clinical staff—including attending physicians, residents, nurse practitioners, physician assistants, and temporary (locum tenens) providers. The high turnover and rotating schedules typical in emergency medicine can make it difficult to keep provider credentials up to date with all payers, increasing the risk of these denials.
Prevention:
- Implement a comprehensive provider enrollment tracking system
- Create a credentialing calendar with renewal deadlines
- Establish onboarding protocols that prioritize immediate credentialing applications
- Develop clear protocols for billing under supervising physicians when appropriate
- Understand payer-specific rules for billing resident services
- Implement software that prevents claim submission for non-credentialed providers
Conclusion
Emergency medicine faces unique revenue cycle challenges due to the urgent, unplanned nature of care. By targeting the top denial reasons with focused prevention strategies, departments can boost clean claim rates and reduce administrative workload. Success depends on balancing quick care delivery with accurate information capture and strong back-end processes. Investing in staff training, technology, and workflow improvements can greatly reduce denials. Conducting a denial analysis helps identify key problem areas and guide improvements. Denial prevention should be an ongoing effort, adapting to payer changes and evolving best practices. Prioritizing denial management allows providers to focus more on patient care.