Top 10 Denials in Medical Billing

Top 10 Denials in Medical Billing And How To Solve Them

Some of the most common challenges within the healthcare industry are related to the dreaded medical billing denials. Denials can lead to delayed payments and increased administrative burdens. That’s why, in this article, we want to cover the top 10 denials in medical billing and provide strategies for mitigating them.

AR Denials in Medical Billing

Short for account receivable, AR denial in medical billing is used to describe the amount of money insurance companies and other third-party payers owe your healthcare providers

Denials occur once you’ve submitted your claims and the insurance company has processed the claim. When you’re met with a denial, the insurance payer refuses to reimburse the services you’ve offered due to an issue or error in the claim.

As expected, this can significantly impact your healthcare organization’s revenue cycle and cash flow.

Unfortunately, denials can delay the time to get reimbursed for the services, affecting your ability to cover operating expenses. If they’re not resolved, your healthcare organization will experience a reduction in revenue, which may lead to financial instability.

Identifying and appealing denied claims comes with additional administrative costs. Failing to address and manage them may result in penalties, audits, or legal consequences due to compliance issues with billing regulations.

What Are Denial Codes?

These alphanumeric codes are assigned by insurance companies and act as a standardized way of communication about the reasons behind the denial. Since they elaborate on the errors that have led to the denial, your healthcare providers and billing staff can use them to identify the appropriate actions to address the issue. 

Denial codes are most commonly found in electronic remittance advice (ERA) files, denial letters, or explanations of benefits (EOB) sent by the insurance company. 

Medical Billing Denial Codes and Solutions

Based on our latest findings, here are the top 10 most common denial codes and the best ways to solve them:

  1. Missing primary insurance information
  2. Coding errors
  3. Lack of medical necessity
  4. Timely filing denials
  5. Duplicate claims
  6. Coordination of Benefits (COB) issues
  7. Incomplete documentation
  8. Eligibility issues
  9. Service not covered
  10. Incorrect provider information

1. Missing Primary Insurance Information

This denial occurs when the insurance payer receives a claim but finds that the necessary information about the patient’s primary insurance is either incomplete or missing. This can prevent the payer from processing the claim correctly. Since the primary insurance information is not provided, it is unclear which insurance is responsible for paying the claim.


The first solution to this denial is to prevent it from happening by verifying the patient’s insurance information. During patient registration, confirm and document all insurance policies the patient holds. You should ensure the primary insurance details are accurately recorded, including policy numbers, group numbers, and subscriber information.

If the denial has already occurred, what you should do next is to resubmit a corrected claim. You should obtain the missing primary insurance information from the patient or their records. This will allow you to correct the claim and include all primary insurance details. Resubmit the claim to the secondary insurance with the primary insurance information and Explanation of Benefits (EOB) from the primary insurer, if applicable.

By ensuring that primary insurance information is accurately collected and submitted, healthcare providers can reduce the likelihood of this type of denial and improve the efficiency of their claims processing.

Missing Primary Insurance Information

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2. Coding Errors

Codding errors occur due to mistakes or inaccuracies regarding diagnostic and procedural codes used to describe the medical treatments and services provided to patients. In most cases, these errors happen while translating medical documentation into standardized codes for billing purposes.

The most common coding issues we’ve seen in medical billing are missing codes, inaccurate code selection, upcoding, downcoding, and incorrect modifier usage. There are two standardized sets of codes– CPT and ICD. 

  • CPT (Current Procedural Terminology) codes –  developed by the AMA (American Medical Association) and used to describe diagnostic, medical, and surgical services provided by healthcare providers.
  • ICD (International Classification of Diseases) codes –  developed by the WHO (World Health Organization) used to describe diagnoses, symptoms, and procedures during patient treatment. The two categories of ICD-10 codes you should know are CM for Clinical Modification and PCS for Procedure Coding System. While the first are used to describe diseases, injuries, and symptoms, the latter are used for procedures and treatments.


The best way to prevent coding errors from happening is to provide thorough coding training for your staff and conduct regular audits to ensure billing accuracy. First, you must ensure that your medical and billing staff is up-to-date with the latest coding regulations, guidelines, and practices. 

By conducting regular coding audits, you can identify potential coding errors, compliance issues, and inconsistencies in coded medical records. You can also utilize various tools and software to review the coding and documentation accuracy.

Even though it takes continuous efforts to ensure flawless billing practices, keeping track of the latest updates regarding coding regulations is important because they’re subjected to frequent changes.


Source: Photo Contributor: chaylek

3. Lack of Medical Necessity

Codes representing lack of medical necessity are the third most common denial in medical billing. In such cases, the insurance company has determined that the treatment was non-essential for the patient’s condition. One of the main reasons insurance payers may believe that the services aren’t a medical necessity is that you may be missing sufficient medical documentation to support the claims.

Thus, the most common denial codes you may come across in this instance are the following:

  • CO50– Non-covered services because they’re not considered a medical necessity
  • CO57– the payment has been denied or reduced because the insurance payer deems the information submitted doesn’t support the level of service


The best way to prevent denials based on lack of medical necessity is to encourage your physicians to provide comprehensive documentation to support the claims. To prevent a disruption in the revenue cycle, insurance payers need to focus on coverage policies and look through the patient’s medical history. 

Lack of Medical Necessity

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4. Timely filing denials

Many insurance companies include predetermined time frames within their policies in which you need to submit your claim. Each insurance company has its specific deadlines you should be aware of, also referred to as timely filing limits

Failing to submit your claim within the given timeframe will result in denials and missed reimbursement opportunities. That being said, the most common reasons for these timely filing denials are missed deadlines, delayed processing, and administrative errors.


Even though you can appeal this denial or resubmit the claim for reconsideration alongside documentation supporting the delay, it’s best to implement strategies that prevent this issue altogether. The best way to avoid timely filing denials is by monitoring filing deadlines and prioritizing timely claim submissions.

First, you can implement reminders and alerts, such as billing systems, scheduling software, and electronic calendars, to inform you about upcoming deadlines. This way, both you and your staff will be able to easily identify high-priority claims and submit them on time.

Next, you should try and optimize the claim submission workflow. By utilizing electronic claim submission systems and automated coding tools, you can minimize administrative burdens and delays.


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5. Duplicate claims

As the name implies, these errors happen when you’ve submitted a claim with information identical to a previous claim, including the same patient, provider, and service date. Insurance companies have systems to prevent duplicate claims, so it is advisable you never submit the same claim twice. 

Other instances of duplicate claims occur when you’ve resubmitted a claim without indicating that it’s been corrected or if you’ve provided the same services on the same days without using a modifier. Thus, the common denial codes you may come across are the following:

  • CO18 – Duplicate claim or service
  • CO97 – The benefit for the service is included in the payment for another service that has already been adjudicated


By using billing systems with automated claim scrubbing features, you can compare the claim you’re about to submit with the existing ones in the system. This way, you can identify the source of the duplicate claim and take corrective action to prevent this issue from happening again.

Duplicate Claims

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6. Coordination of Benefits (COB) issues

Next, you should watch out for denial codes regarding COB (Coordination of Benefits) issues. The coordination of benefits is set in place to prevent overpayment or duplication of benefits by governing how multiple insurance plans coordinate their payments.

The most common denial code in such instances is CO22, indicating that another payer has covered the service per coordination of benefits. As mentioned, this issue can arise when the patient you’ve treated has multiple insurance plans by primary, secondary, or tertiary insurance providers.


To avoid such denials, you must gather and verify the needed insurance information as soon as the patient visits your healthcare organization. First, you must always encourage patients to provide accurate data about their multiple insurance coverages. Then, you should verify and update their information through your designated software to ensure accurate coordination of benefits.

Once you’ve documented this data, you submit your claim with the appropriate COB information, including primary, secondary, and tertiary insurance details.


Source: Photo Contributor: Andrey_Popov

7. Incomplete documentation

Incomplete documentation occurs when your claim has missing or insufficient information to support the services you’re billing for. Such information can include simple demographic data you may have missed from the patient, including social security numbers and addresses or appropriate billing requirements like modifiers.

Furthermore, you should be aware that different insurance companies have unique requirements regarding the necessary information needed. So, you should always check their guidelines to ensure you meet the standards of the insurance payer for claims processing.


Besides informing yourself about the provider’s requirements, you should always double-check if you have all the needed documentation before submitting the claim to avoid such denials. That being said, some of the most common information you’ll need to acquire is the following:

  • Patient demographic details (name, address, date of birth, contact, and insurance information) 
  • Provider information(name, contact information, NPI (National Provider Identifier), and TIN (Tax Identification Number)).
  • Diagnostic and procedural codes– assigning accurate codes such as ICD and CPT codes for billing purposes, as well as the appropriate modifiers.
  • Clinical documentation– medical documentation regarding test results, treatment plans, and progress notes to support the medical necessity of the services.
  • Date of service– appropriate dates of service for each service you’re billing for that align with the documentation and medical necessity.
  • Authorization information– referral numbers and authorization documentation that ensure the services you’ve provided have been authorized as noted in the payer’s requirements.
Incomplete Documentation

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8. Eligibility issues

Even though they’re not as frequent as the previous denial codes, you may also come across ones about eligibility issues. When this happens, the insurance company refuses to reimburse your services because the patient’s insurance coverage can’t be verified or doesn’t meet the necessary criteria.

The two main reasons for eligibility issues are either an inactive or expired insurance policy. Even though both statuses indicate that the insurance coverage isn’t valid, an inactive insurance policy can be either temporarily suspended or not in effect, while an expired one means that it has reached the end of the coverage period. 


The best way to prevent eligibility issues is to verify the patient’s information before offering services. Even though you can always contact the insurance company to confirm the coverage status, we recommend implementing electronic eligibility verification tools to automate the process. Remember that you should also be mindful of the patient’s insurance benefits and prior authorization to avoid further delays.

Eligibillity Issues

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9. Service not covered

During the medical billing process, you may also come across denial codes for services not covered. Similar to eligibility issues, this error occurs when the patient’s insurance plan doesn’t cover the services you’ve provided for them. This can include specific procedures, treatments, and supplies the patient needs while at your healthcare facility. 

The main reasons for these issues are if the services you’ve provided exceed the insurance plan’s benefit limits, are excluded from coverage, or if the needed prior authorization wasn’t obtained.


Once again, the main solution to this problem is to verify the patient’s insurance policy details before you offer any services. Familiarizing yourself with the procedures and treatments that need prior authorization will help you obtain the said authorization before you begin treating the patient. Therefore, it’s important to provide proper training and education for your staff and get up-to-date information about the patient’s insurance.

Service not covered


10. Incorrect provider information

The last denial code we want to elaborate on refers to incorrect provider information. As mentioned, this data is essential for submitting your claim, and failing to provide it can lead to missing or inaccurate documentation. 

When it comes to provider information, remember that you should always double-check the name, NPI (National Provider Identifier), and TIN (Tax Identification Number). Furthermore, your healthcare providers should be enrolled with the specific payers so you can be reimbursed for the services offered. 


To avoid such denials, you should always ensure accurate provider information is entered into the billing system and claims. Besides reviewing the provider details to see if it matches the payer’s records, you should also update this data when there’s been a change in the name, credentials, NPI, and TIN. The three main components of preventing such denials are regular review and verification of provider information, ongoing communication with payers, and staff training on claim submission procedures. 


Source: Photo Contributor: Linaimages

Importance of Denial Management

After elaboration on the most common denial reasons and their solutions, we want to highlight the importance of proper denial management. As mentioned, failing to get reimbursed for the services offered can seriously harm your revenue cycle and lead to financial instability.

That being said, the four main steps this process consists of are the following:

  • Identification
  • Analysis
  • Appeals
  • Tracking results and follow-ups
  • By addressing the most common issues regarding denials, you can maximize your revenue through timely and accurate reimbursement for services. Moreover, it enhances your operational efficiency, leading to reduced financial losses and improved cash flow. 


After elaborating on the top 10 denials in medical billing, we hope this article helps explain the best ways to solve them. Remember that appropriate denial management is essential for swiftly overcoming these issues and getting properly reimbursed. Since denials can greatly affect your healthcare organization’s revenue cycle and financial stability, it’s important to set up the appropriate measures to avoid any revenue loss.That’s why our team at CLICKVISION BPO has a sector specializing in providing optimized back office healthcare operation services designed to meet the diverse needs of healthcare organizations. Whether you need help with medical billing and coding or require end-to-end outsourcing services in the healthcare sector, we offer tailored solutions to optimize your business operations. So, contact our team at Clickvision BPO today and discover how we can help you achieve unparalleled results!

With a strong background in the marketing industry and healthcare leadership roles, Filip is responsible for CLICKVISIONBPO's sales strategies and onboarding new clients. With a passion for sharing insights gained from his experience, he also shares valuable knowledge through industry related articles.