Medical billing can feel like a maze. One wrong step and the claim comes back denied, costing time, money, and patience. But here’s the good news: once you understand why denials happen and how to fix them, the whole process feels less like solving a puzzle and more like following a clear roadmap.
Think of denials like traffic signals. If you know what each light means, you can avoid unnecessary stops. In the same way, decoding denial codes helps medical practices get paid faster and reduce delays.
In this guide, we’ll walk through the top 10 common medical billing denials, why they occur, what the denial codes mean, and, most importantly, how to fix or prevent them.
What Is a Medical Billing Denial?
A denial means the insurance company refuses to pay a claim because something is wrong, missing information, incorrect coding, the patient is not eligible, or simple technical mistakes.
To put it simply:
A denial is the insurance company’s way of saying, “Fix this first.”
Why Understanding AR Denials Matters?
AR (Accounts Receivable) denials slow cash flow, reduce revenue, and increase the workload for billing teams. If you know the standard denial codes, you can fix patterns before they grow into bigger problems.
Understanding AR denials also helps with:
- Faster reimbursements
- Lower claim rejections
- Fewer appeals
- More accurate billing documentation
Also Read: Cardiology Medical Billing Solution to Resolve Denials
The Top 10 Denials in Medical Billing (With Codes)
Below are the most common top 10 denial codes in medical billing, based on real medical billing scenarios across specialties. We’ll break down each denial, explain the code, and offer simple solutions.
Denial #1: CO 11 – Diagnosis Inconsistent With Procedure
What It Means:
The insurance company thinks the diagnosis doesn’t match the procedure billed.
Example:
A procedure meant for diabetes management is billed with a hypertension diagnosis.
Why It Happens:
- Wrong diagnosis-to-procedure mapping
- Documentation mismatch
- Coding errors
How to Fix:
- Review ICD-10 & CPT compatibility
- Verify provider notes
- Update diagnosis codes
Denial #2: CO 29 – Past Filing Limit
What It Means:
The claim was submitted too late.
Why It Happens:
- Delays in Documentation
- Issues in the claim submission workflow
- Incorrect insurance on file
How to Fix:
- Submit claims within the payer’s time frame
- Track filing deadlines
- Correct insurance data at the front desk
Denial #3: CO 119 / PR 119 – Benefit Maximum Reached
What It Means:
The patient has already used up their insurance benefit for the service.
Why It Happens:
- Lack of eligibility checks
- Incorrect benefit assumptions
How to Fix:
- Verify coverage limits before rendering services
- Inform the patient about out-of-pocket options
Denial #4: CO 167 – Diagnosis Not Covered
What It Means:
The diagnosis code is not payable for the service billed.
How to Fix:
- Review payer policy
- Update diagnosis based on Documentation
- Resubmit with the correct medically necessary codes
Denial #5: CO-16 – Missing or Invalid Information
What It Means:
Something is missing: NPI, modifiers, DOB, insurance ID, CPT code, or provider info.
How to Fix:
- Double-check the claim form
- Use claim scrubbers
- Ensure complete Documentation
Denial #6: PR 3 – Patient Responsibility
What It Means:
The patient owes deductibles, co-insurance, or copay.
How to Fix:
- Collect payments upfront
- Communicate benefits clearly
- Verify eligibility
Denial #7: PR 276 – Eligibility Issues
What It Means:
The patient was not eligible on the date of service.
How to Fix:
- Verify insurance on every visit
- Recheck coverage through portals
- Correct insurance details
Denial #8: Denial Code 18 – Duplicate Claim
What It Means:
The insurance company thinks you submitted the same claim twice.
How to Fix:
- Check claim history
- Avoid resubmitting without correcting errors
- Appeal if it was not a duplicate
Denial #9: Denial Code 97 – Service Not Covered
What It Means:
The service is not included in the patient’s insurance plan.
How to Fix:
- Confirm coverage before service
- Provide alternative treatments
- Inform the patient ahead of time
Denial #10: CO-B11 – Coordination of Benefits Required
What It Means:
The insurance needs to confirm which plan is primary or secondary.
How to Fix:
- Ask the patient to update COB
- Contact insurance
- Resubmit after verification
Types of Denials in Medical Billing
A. Hard Denials
These cannot be corrected. The practice won’t get paid.
Example: Filing limit passed permanently.
B. Soft Denials
These can be corrected, appealed, or resubmitted.
Example: Missing modifier, incorrect diagnosis, wrong insurance.
C. Clinical Denials
Related to medical necessity.
D. Administrative Denials
Related to errors in the claim form.
Also Read: Overcoming Insurance Denials in Mental Health Billing
Medical Billing Denials and Actions (Fixes & Prevention)
Here’s how to reduce AR denials in medical billing:
1. Verify Patient Eligibility
Most denials happen due to outdated or incorrect insurance information.
2. Use Accurate Coding
Incorrect CPT/ICD-10 leads to CO 11, CO 167, CO-16, etc.
3. Improve Documentation
Clear provider notes prevent diagnosis mismatches.
4. Monitor Denial Trends
If CO 29 or CO 119 keeps recurring, it’s a systemic issue.
5. Train Staff Regularly
Billing guidelines change often.
6. Use Claim Scrubbers
Automated tools catch errors before claims go out.
7. Submit Timely Claims
Avoid CO 29, late filing.
8. Appeal When Needed
Many denials can be overturned with proper Documentation.
FAQs
1. What are the top 10 denials in medical billing?
They include CO 11, CO 29, CO 119, CO 167, CO 16, PR 3, PR 276, denial code 18, denial code 97, and CO-B11.
2. What is denial code 119 in medical billing?
It means the patient has reached their benefit maximum for the service.
3. Why do medical claims get denied?
Common reasons include incorrect information, coding errors, lack of eligibility, late filing, or non-covered services.
4. What is the CO-16 denial code?
It means the claim has missing or incorrect information.
5. How do you avoid medical billing denials?
By verifying eligibility, accurate coding, timely submissions, correct Documentation, and reviewing denial patterns.
Conclusion
Medical billing denials don’t have to feel overwhelming. When you understand the top 10 denial codes in medical billing, why claims get rejected, and how to fix them, you gain control over your revenue cycle.
Just like learning the rules of the road helps you drive safely, understanding denial codes helps your practice move smoothly, without unexpected stops.
