By Ahmad Bashir · Updated October 26, 2026
A denial means the payer processed a claim and refused to pay it. Every denial costs staff time to rework, and some are never recovered. The good news is that most denials come from a short list of repeat causes.
The 10 most common denial reasons
1. Inactive coverage or eligibility problems
The patient’s plan has ended or changed, or it does not cover the service. Prevent it: verify eligibility before every visit, not only the first one.
2. Missing or incorrect patient information
A misspelled name, wrong date of birth or incorrect member ID is enough to stop a claim. Prevent it: check demographics against the insurance card at check-in.
3. Missing prior authorization
A service that needs payer approval was performed without it, or after the approval expired. Prevent it: check authorization rules when the service is scheduled, and track approvals and their end dates.
4. Coding errors
Wrong, outdated or mismatched CPT and ICD-10 codes. Prevent it: review codes before submission and keep up with annual code updates.
5. Missing or incorrect modifiers
A modifier that changes how a service is paid is missing or used incorrectly. Prevent it: check each payer’s modifier rules, especially for services billed on the same day.
6. Lack of medical necessity
The diagnosis on the claim does not support the service under the payer’s coverage policy. Prevent it: make sure documentation and diagnosis codes support every service billed.
7. Duplicate claims
The same service is billed twice, often when a claim is resubmitted instead of followed up. Prevent it: check claim status before sending a claim again.
8. Bundling edits
The payer treats a service as part of another procedure on the same claim. Prevent it: scrub claims against bundling edits, and use modifiers only when documentation supports a separate service.
9. Coordination of benefits issues
The wrong payer was billed as primary, or the payer needs updated information about other insurance. Prevent it: confirm primary and secondary coverage at each visit.
10. Missed timely filing deadlines
Every payer limits how long after the date of service a claim can be filed. Medicare generally allows 12 months, and many commercial payers allow much less. Prevent it: submit promptly and fix rejections quickly so claims stay inside the window.
How to bring your denial rate down
Track every denial by reason and payer. Within a few months, patterns appear: one payer rejecting a certain modifier, or one front-desk step that keeps getting skipped. Fixing the cause, not just the claim, is what lowers your denial rate over time.
If denials are piling up, I can work through them and set up a prevention plan. See denial management services.