Introduction
For neurology practices, denied claims aren’t just an inconvenience they’re a costly disruption that can quietly erode annual revenue. With denial rates in the specialty often hovering between 15% and 20%, the impact on practice performance, patient access, and financial stability is significant.The nature of neurology with its reliance on advanced diagnostics, long-term treatment plans, and highly specific procedural coding makes it especially vulnerable to billing and documentation errors. From nerve conduction studies and imaging to infusion therapy and migraine management, each service requires a detailed and accurate claim submission to avoid delays or outright denials.
In this post, we’ll explore the 10 most frequent denial codes affecting neurology practices, examining how they arise and why they disproportionately affect neurological services. With a better understanding of these denials and how to address them, neurology teams can reduce delays, lower costs, and get paid for the work they do.
Common Denial Codes in Neurology
| Denial Code | Description |
|---|---|
CO 50 | Not Medically Necessary Service |
CO 197 | Precertification/authorization missing |
CO 234 | Procedure not paid separately/bundled |
CO 97 | Global period inclusion |
CO 16 | Missing/invalid claim info |
CO 96 | Non-covered charge(s) |
CO 151 | Provider type not eligible |
CO 4 | Modifier inconsistent |
CO 204 | Service not covered under patient’s current benefit plan |
CO B7 | Provider not credentialed/authorized |
Detailed Analysis of Top 10 Denials
1. Denial Code: CO 50
Description: Medical Necessity Denials
Medical necessity denials happen when insurance companies decide a neurological service wasn’t needed based on their coverage rules. These denials are common in neurology, especially for services like Botox injections for migraines, long-term EEG monitoring, or repeated MRI scans. Claims are often rejected if the medical records don’t clearly explain why the test or treatment was required, if lower-cost options weren’t tried first, or if the service was performed more often than guidelines allow.
For instance, an EEG may be denied if there’s no clear evidence in the notes pointing to suspected seizure activity. Similarly, Botox for migraine can be denied if the provider didn’t document that the patient tried and failed more standard treatments first. Because many of these neurological services come with high reimbursement rates, frequent denials like these can have a serious effect on a practice’s income.
Prevention:
- Develop complete documentation templates specific to common neurological treatments (Botox, EEG, neuroimaging)
- Create clear guidelines for physicians on documenting the medical necessity for neurological procedures
- Implement clinical decision support tools aligned with evidence-based guidelines
- Document failed conservative treatments before advancing to more specialized interventions
- For follow-up or repeat studies, clearly document changes in clinical status justifying additional testing
2. Denial Code: CO 197
Description: Missing Precertification/Authorization
Authorization denials happen when a neurological service is performed without the required pre-approval from the insurance company. In neurology, this often affects advanced imaging (such as MRIs or PET scans), sleep studies, infusion therapies for conditions like multiple sclerosis, and Botox treatments for chronic migraines. These denials can be particularly costly, as they typically result in no reimbursement at all even for high-cost procedures.
One of the biggest challenges is timing. Many neurological conditions require quick action, and waiting for prior approval isn’t always feasible in urgent situations, such as a possible stroke or sudden neurological decline. On top of that, each insurance plan has its own set of authorization rules, making it hard for staff to keep up especially given the wide range of services neurology covers. This adds to the administrative workload and increases the risk of missed approvals.
Prevention:
- Develop a robust tracking system for neurological procedure authorizations
- Train scheduling staff on specific authorization requirements for common neurology procedures
- Establish protocols for urgent/emergent situations requiring retrospective authorization
- Document all authorization numbers, dates, and specifics in both clinical and billing systems
- Verify authorization status before delivering neurological services
3. Denial Code: CO 234
Description: Bundled Procedure Denials
Bundling denials arise when separate charges are submitted for services that the insurance company considers part of a single procedure. In neurology, this often involves electromyography (EMG) and nerve conduction studies (NCS), which some payers require to be billed together using a single comprehensive code. Similar issues can occur when multiple neurological tests are performed on the same day like several autonomic function tests or different parts of a cognitive evaluation and are billed individually.
These denials can be especially frustrating, as they demand a deep understanding of each payer’s bundling rules, which often differ from standard coding practices or vary between insurers. Keeping up with these differences is essential to avoid payment delays or losses.
Prevention:
- Stay current on NCCI (National Correct Coding Initiative) edits affecting neurological services
- Create a reference guide for commonly bundled neurological procedures by payer
- Implement claim scrubbing software with neurology-specific edits
- Train coders on proper use of comprehensive codes versus component codes
- Understand payer-specific policies for EMG/NCS coding combinations
4. Denial Code: CO 97
Description: Global Period Inclusion Denials
Global period denials happen when services provided after a neurological surgery are billed separately, even though they fall within the surgery’s designated global period. In neurology, this often affects follow-up procedures like EMGs, EEGs, or wound care performed after surgeries such as craniotomies, shunt placements, or spinal operations. These surgeries come with a global period usually 10, 30, or 90 days during which routine follow-up care is already included in the payment for the original procedure.
If a service performed during that time is related to the surgery, it won’t be reimbursed unless it’s clearly documented and coded to show it was unrelated or separately billable. This creates a unique challenge for neurology practices, as many patients require ongoing care that may overlap with the global period but still warrants separate attention especially in cases involving complex or evolving neurological conditions.
Prevention:
- Maintain current knowledge of global period assignments for common neurosurgical procedures
- Create procedure-specific guidelines for global period management
- Train providers on documentation requirements for services outside the global package
- Properly use modifiers (-24, -25, -78, -79) to indicate unrelated or distinct services
- Implement tracking systems for patients in global periods
5. Denial Code: CO 16
Description: Missing or Invalid Claim Information
Technical denials occur when a claim is rejected because it is missing important details or contains incorrect information. Common issues in neurology include incomplete ICD-10 codes for conditions like seizures or multiple sclerosis, missing or incorrect modifiers on EEGs with office visits, or incomplete documentation for complex neurological assessments.
Given the detailed nature of neurological diagnoses, which require accurate coding to reflect the full clinical picture, these denials are common. Ensuring that all required information is correctly submitted is crucial to avoiding these types of rejections.
Prevention:
- Train staff on proper use of modifiers for neurological services
- Develop diagnosis code reference guides for common neurological conditions
- Verify all required elements are present before claim submission
- Create standardized documentation templates for common neurological procedures
- Implement quality control reviews before claim submission
6. Denial Code: CO 96
Description: Non-covered Service Denials
Non-covered service denials occur when a neurological treatment or procedure is not included in the patient’s insurance plan. In neurology, this often involves newer therapies like vagus nerve stimulation (VNS), CGRP inhibitors for migraines, or other specialized treatments that some insurers may classify as investigational or experimental. Unlike medical necessity denials, these services are excluded from coverage regardless of whether they are clinically justified.
These denials present a significant challenge, as they can leave patients responsible for the full cost of expensive treatments. They can also create obstacles to accessing cutting-edge therapies that could benefit patients with complex neurological conditions.
Prevention:
- Verify specific coverage for planned neurological treatments during insurance verification
- Create a database of commonly non-covered neurological services by payer
- Implement advance beneficiary notice (ABN) protocols for Medicare patients
- Develop similar financial responsibility forms for commercial payers
- Train scheduling staff to identify potentially non-covered neurological services
7. Denial Code: CO 151
Description: Provider Type Not Eligible
These denials occur when claims are submitted for services that insurers believe can only be provided by certain types of providers. In neurology, this often affects cognitive testing (e.g., CPT codes 96125, 96136), which may be denied if the neurologist isn’t recognized as a psychologist or behavioral health provider by the payer. Similarly, certain specialized neurological treatments or assessments may be limited to providers with specific credentials or specialties beyond general neurology.
These denials can be particularly frustrating because neurologists may have the necessary training and expertise to perform these services, but insurer policies may not acknowledge their qualifications in these areas.
Prevention:
- Research payer-specific policies regarding provider types eligible for neuropsychological testing
- Develop relationships with medical directors at major payers to educate them about neurology training and scope
- Consider collaborative care models with recognized provider types when needed
- Maintain documentation of specialized training or certification for neurological services
- Appeal inappropriate provider type restrictions with supporting documentation of qualifications
8. Denial Code: C0 4
Description: Modifier Inconsistency Denials
These denials occur when modifiers are applied incorrectly to service codes. In neurology, this frequently involves the use of modifier -25 (for a significant, separately identifiable E/M service) when billing for both an office visit and a procedure, such as an EMG or Botox injection, or modifier -59 (for distinct procedural services) when multiple neurological procedures are performed on the same day.
Incorrectly applied modifiers can result in automatic claim rejections, while missing modifiers can lead to inappropriate bundling of services or lower reimbursement. Given the complexity of neurological care, which often involves both cognitive assessments and procedural treatments during the same visit, using the right modifiers is crucial but can be especially tricky.
Prevention:
- Train providers and coders on appropriate use of modifiers -25 and -59 in neurology
- Create quick-reference charts showing which neurological service combinations require modifiers
- Implement claim scrubbing tools that verify proper modifier usage
- Conduct regular audits of modifier usage on high-risk neurological service combinations
- Stay updated on payer-specific modifier requirements for neurological services
9. Denial Code: C0 204
Description: Service Not Covered Under Patient’s Plan
These denials occur when a specific neurological service is not covered under a patient’s insurance plan, often involving specialized medications or treatments. In neurology, this frequently impacts newer therapies like CGRP inhibitors for migraines (such as Aimovig or Emgality), which may not be included in the payer’s formulary, specialized infusion treatments for conditions like multiple sclerosis or myasthenia gravis, or advanced diagnostic procedures.
Unlike general non-covered service denials (CO-96), these services might be covered under other plans from the same insurer but are excluded from the patient’s particular plan. These denials pose a unique challenge in neurology due to the rapid development of new treatments and the high costs associated with many cutting-edge neurotherapeutic options.
Prevention:
- Verify specific plan coverage for newer neurological medications and treatments
- Implement drug formulary checking processes before prescribing specialty neurological medications
- Create a database of commonly restricted neurological treatments by specific plans
- Develop protocols for obtaining formulary exceptions for neurological medications
- Train staff on plan-specific verification for high-cost neurological therapies
10. Denial Code: CO B7
Description: Provider Not Credentialed/Authorized
These denials occur when claims are submitted for a provider who is not properly enrolled, credentialed, or authorized to deliver services under the patient’s insurance plan. In neurology, this often involves EEG interpretation services, infusion billing for specialty medications, or newly hired neurologists whose credentialing process hasn’t been fully completed with all insurers.
These denials can be especially challenging for neurology practices that have multiple subspecialties or employ neurophysiology technicians, as each provider needs to be individually credentialed for their specific role and the services they offer. Given the highly specialized nature of many neurological services, ensuring that credentialing is in place for all providers across every payer is both essential and complex.
Prevention:
- Create a credentialing calendar with renewal deadlines for all payers
- Verify provider credentialing status before scheduling patients
- Develop clear protocols for billing under supervising physicians when appropriate
- Understand payer-specific rules for neurophysiology technicians and supervised services
- Implement software that prevents claim submission for non-credentialed providers
Conclusion
Neurology practices face unique billing challenges due to the complexity of conditions, specialized testing, and frequent updates in treatment approaches. These factors contribute to a higher risk of insurance denials, which can significantly impact revenue and patient access to care.Reducing denials starts with accurate patient and insurance verification, strong documentation habits tailored to neurological services, and close coordination between clinical and billing staff. High-denial areas, such as EEGs, infusions, or advanced diagnostics, benefit from clearly defined billing workflows.
A focused review of denial trends in your practice can highlight where the biggest gaps lie. Addressing these issues through targeted training and process improvements helps reduce rework and lost payments.Denial prevention isn’t a one-time task—it requires consistent attention and adaptability. By making it part of your regular operations, your practice can reduce disruptions, maintain financial health, and better support patients who rely on timely, specialized neurological care.