Every year, the American Medical Association (AMA) updates the Current Procedural Terminology (CPT) code set with new codes, revised descriptors, deleted codes, and updated guidelines. And every year, practices without a structured update process end up submitting claims with outdated or incorrect codes, which leads to denials, underpayments, and compliance risk.
The problem is rarely that teams do not know updates exist. It is that the specific changes get lost in the daily workload. These are the ten mistakes that show up most often in denial data and coding audits.
10 CPT Coding Mistakes Practices Are Making This Year
1. Billing Deleted Codes
Each annual CPT update deletes codes that have been replaced or consolidated. Practices with outdated superbills, templates, or EHR order sets sometimes keep submitting deleted codes for months, which causes automatic denials.
Fix: Audit and update superbills, EHR charge templates, and encounter forms every January when the new code set takes effect.
2. Missing New Codes for Emerging Services
New CPT codes are often added for services that used to be billed with unlisted or generic codes, including remote physiologic monitoring, digital therapeutics, and behavioral health integration. Practices that keep using the old workaround codes often get paid less than the new, more specific code would pay.
Fix: Each year, compare new codes for your specialty against services you currently bill with unlisted or unspecified codes.
3. Misusing Add-On Codes
Add-on codes cannot be billed alone and must accompany a primary procedure code. They are a frequent cause of denials when billed alone or with the wrong primary code, and annual updates sometimes change which primary codes an add-on can be paired with.
Fix: Keep an up-to-date list of add-on codes and their approved primary codes, and set billing software edits to flag mismatches before submission.
4. Using Modifiers 25 and 59 Incorrectly
Modifier rules are refined almost every year, including when modifier 25 (significant, separately identifiable E/M service) and modifier 59 (distinct procedural service) apply. Payers scrutinize both closely, and overusing them is one of the top audit triggers. Medicare also prefers the more specific X modifiers (XE, XP, XS, and XU) over modifier 59 when one of them describes the situation, and many commercial payers have followed.
Fix: Review each payer’s modifier policies every year, not only CPT guideline changes, because commercial payers often apply stricter rules than Medicare.
5. Miscoding Time-Based E/M Services
Evaluation and management (E/M) coding continues to change, especially around time-based coding versus leveling by medical decision-making (MDM). Practices that have not retrained staff on current E/M guidelines often fall back on old habits, which creates both underbilling and overbilling risk.
Fix: Hold annual E/M refresher training for providers and billers. Documentation habits, not only code selection, determine whether time-based or MDM-based leveling holds up in an audit.
6. Ignoring Quarterly NCCI Bundling Edits
National Correct Coding Initiative (NCCI) edits define which code pairs cannot be billed together, and they are updated quarterly. Practices that review coding changes only once a year miss these updates entirely.
Fix: Add a quarterly NCCI edit review to your billing calendar, separate from the annual CPT review.
7. Not Updating Fee Schedules for New Codes
When codes are added or revised, practices sometimes forget to update their internal fee schedules. New codes end up billed at $0 or at outdated rates that do not match current payer contracts.
Fix: Make fee schedule updates a required step in your annual CPT update process.
8. Overlooking Category III Code Changes
Category III codes cover emerging technology and procedures. They are updated twice a year and are often converted to permanent Category I codes or deleted. Billing a Category III code after it has been replaced leads to automatic denials.
Fix: Track Category III changes on their own twice-yearly schedule.
9. Applying Last Year’s Telehealth Coding Rules
CPT updates periodically change which services need telehealth modifiers or place-of-service codes and which are billed with standard in-person codes. Practices using last year’s telehealth billing logic for this year’s codes are a common source of denials.
Fix: Each year, check your telehealth billing rules against both current CPT guidelines and current payer policies, since the two do not always change at the same time.
10. Not Auditing Claims After the Update
Many practices update their code sets but never audit claims submitted in the following weeks to confirm the changes were applied in every system: the EHR, the clearinghouse, and the billing software.
Fix: Audit a sample of claims 30 to 60 days after each annual CPT release to catch any system that did not update correctly.
Why These CPT Mistakes Keep Happening
Most of these errors share one root cause: CPT updates are treated as a once-a-year event instead of an ongoing process that touches several systems at once, including EHR templates, billing software, fee schedules, payer contracts, and staff training.
Practices with in-house coding compliance staff catch these issues faster. Smaller practices without that role often let updates slip between the front desk, the providers, and whoever handles billing part-time.
Outsourced billing and coding partners are designed to close this gap. FAS Medical Summit includes coding compliance review in its revenue cycle management services, tracking annual CPT updates, quarterly NCCI edits, and Category III changes, and preparing clients for larger shifts such as the move to ICD-11.
Quarterly Checklist to Reduce CPT-Related Denials
If you manage billing in-house, this checklist catches most of the errors above:
- Review CPT code additions and deletions for your specialty
- Update EHR templates and superbills
- Check add-on code pairings
- Review payer-specific modifier policies
- Check NCCI bundling edits (quarterly)
- Review Category III code status (twice a year)
- Update fee schedules for new and revised codes
- Audit a sample of claims 30 to 60 days after each update
Put CPT Updates on Your Calendar
CPT updates directly determine whether claims are paid correctly and on time. Practices losing revenue this year usually know updates exist. What they miss are the specific changes in modifier rules, add-on code pairings, and quarterly bundling edits.
A recurring review process is the most reliable way to stop these errors before they become denied claims. If you would rather not build one in-house, contact FAS Medical Summit.
