Denial rates were already rising before you noticed. The national average crossed 11 percent in 2024, up from 10.2 percent the year before. For some specialties and payer mixes, it’s significantly higher.
If your denial rate is climbing, there are five likely causes. Most practices are dealing with more than one at once.
1. Prior Authorization Requirements Expanded
Payers have been adding prior authorization requirements faster than most billing teams can track. Procedures that didn’t require auth six months ago may require it now. Drugs that were covered without pre-approval may now have step therapy requirements.
When a biller submits a claim without required authorization, the denial code is typically CO-15 or CO-197. It looks like a simple authorization denial. What’s actually happening is that your payer quietly updated their coverage policy and your billing workflow didn’t catch it.
The fix: run a payer policy review for your top five payers every quarter. Check for auth requirement changes on your highest-volume CPT codes. This takes about two hours. Most billing teams don’t do it.
2. Eligibility Verification Is Failing at the Front Desk
A patient comes in. The front desk verifies eligibility. The plan is active. The claim goes out. It denies CO-119: not eligible for date of service.
What happened? The patient’s coverage changed. They started a new job. Their employer changed carriers. They aged off their parents’ plan. The verification was done correctly. The data was just wrong at the time of service.
Real-time eligibility verification at the time of check-in catches most of these. Not the day before. Not at scheduling. At check-in, on the day of the appointment, with the actual insurance card in hand.
Eligibility failures are the most common source of preventable denials. They’re also the most preventable.
3. Coding Changes Went Into Effect on January 1
CMS updates CPT and HCPCS codes every January 1. ICD-10 updates go live October 1. When new codes take effect and billing workflows aren’t updated, claims go out with deleted or incorrect codes and deny automatically.
If your denial rate spiked in January or October, code changes are likely involved. Pull your denial report filtered by CO-4 (procedure code inconsistent with modifier) and CO-11 (diagnosis code inconsistent with procedure). Those denial codes point directly to coding mismatches.
4. A Specific Payer Changed Something and Nobody Noticed
Not all denial increases are practice-wide. Sometimes one payer quietly changes a billing requirement, a bundling rule, or a modifier policy, and denials from that payer climb while everything else stays flat.
Pull your denial rate broken out by payer. If one or two payers are driving the increase while others are stable, the problem is payer-specific. That changes how you fix it.
Payer-specific denial spikes usually respond to one of three things: calling the provider relations line to get the updated requirements, submitting a batch appeal with a cover letter citing the prior payment pattern, or requesting a contract clarification in writing.
5. The Denial Queue Is Growing Faster Than It’s Being Worked
This one’s different from the others because it’s not a denial cause. It’s a denial management failure.
A practice can have a stable first-pass denial rate but a rising effective denial rate if the team isn’t keeping up with the work. Denials that aren’t resubmitted within the appeal window become permanent write-offs. The denial rate looks the same on paper. But the collection rate drops because the denials are just aging out instead of being recovered.
Check your denial queue volume versus this time last year. If the queue is bigger, the issue isn’t that more claims are denying. The issue is that fewer are getting worked.
How to Find the Real Cause
Start with your denial report filtered by reason code and payer. Sort by denial count and by dollar value. The highest-volume reason codes tell you what’s happening most often. The highest-dollar codes tell you what’s costing you the most.
If CO-4, CO-11, or CO-97 are in your top five, that’s a coding problem. If CO-15 or CO-197 is near the top, that’s an authorization problem. If CO-119 or CO-96 are leading, that’s an eligibility or coverage issue.
The reason code is the diagnosis. Everything else is treatment.
At Dr. Billerz, we pull the denial breakdown in the first week of every new engagement. We know within seven days what’s driving the denials and have a plan to work through them. The 4-week free pilot includes this analysis at no cost.
Book a 15-minute call and we’ll pull the denial picture for your practice specifically.
Frequently Asked Questions
What is a normal denial rate for a medical practice?
The industry benchmark target is below 5 percent. The national average is currently 11 to 14 percent. If your denial rate is above 10 percent, that’s worth investigating by reason code and payer.
How long do I have to appeal a denied claim?
It varies by payer. Medicare allows 120 days from the date of the denial for a standard appeal. Most commercial payers allow 60 to 180 days. Some plans have shorter windows. Check your payer contract or the denial notice itself for the specific deadline.
Are Medicare Advantage denial rates higher than traditional Medicare?
Yes, significantly. Medicare Advantage plans deny claims at a much higher rate than traditional Medicare. Prior authorization denials in particular are far more common with MA plans. If your MA volume has grown, that alone can drive your overall denial rate up.
Should I fight every denial?
No. Some denials are legitimate. The claims worth appealing are those denied for CO-4 (modifier issues), CO-11 (coding inconsistency), CO-15 (authorization), and CO-97 (bundling). Those are often reversible on appeal. CO-96 (non-covered service) and CO-119 (not eligible) are harder and often not worth the administrative cost unless the dollar value is significant.