What Is Changing in the FY 2027 ICD-10-CM Update?
As of October 1, 2026, the FY 2027 ICD-10-CM code set takes effect, adding 190 new diagnosis codes, deleting 30, and revising 4 across nearly every chapter of the classification. For pediatric practices, the update includes a new dedicated code for hypertrophic pyloric stenosis in childhood (K31.B), expanded specificity in behavioral health and musculoskeletal categories commonly used in adolescent care, and the deletion of codes that will cause automatic claim rejections if still submitted after September 30, 2026.
New pediatric-relevant code. K31.B now gives pediatric coders a dedicated code for hypertrophic pyloric stenosis in childhood, replacing the less specific adult-oriented code previously used for both populations.
30 codes are being deleted. Claims submitted with a deleted code after October 1 will reject automatically. Practices must update EHR templates, superbills, and claim scrubber rules before the cutover date.
October 1 is the hard deadline. The new codes apply to all patient encounters on or after October 1, 2026. There is no grace period for using the old codes after that date.
What CMS Released for FY 2027
In June 2026, CMS and the CDC’s National Center for Health Statistics released the FY 2027 ICD-10-CM code files. The update contains 190 new codes, 30 deleted codes, and 4 revised code descriptions, spanning 33 clinical topics across nearly every chapter of ICD-10-CM. The code set applies to all patient encounters and discharges occurring from October 1, 2026, through September 30, 2027.
Compared to the FY 2026 update, which added over 400 codes, FY 2027 is a moderate update by volume. But the placement of the changes matters more than the count. Several updates land directly in pediatric-relevant categories: digestive system codes that affect how pyloric stenosis is captured, expanded specificity in behavioral and developmental health codes, and musculoskeletal refinements that apply to adolescent sports medicine encounters.
One question we hear constantly from pediatric practice managers is whether a moderate update is safe to skip. It is not. Even a single deleted code left in an EHR template will reject every claim that uses it after October 1. The conversion table CMS published alongside the code files maps each deleted code to its replacement, and that table is the starting point for every practice’s update checklist.
Which New Codes Matter for Pediatric Practices?
The FY 2027 update introduces several codes that directly affect how pediatric encounters are documented and billed. The most significant for daily pediatric coding is K31.B, a new code for hypertrophic pyloric stenosis in childhood. Previously, pediatric coders reported this condition with a less specific code from the K31 category that did not distinguish between the pediatric and adult presentations. K31.B gives practices a dedicated, more specific code that matches the clinical documentation for what is overwhelmingly a pediatric diagnosis.
Other pediatric-relevant additions include expanded codes in the musculoskeletal chapter that separate plantar fasciitis from plantar fascial fibromatosis (previously sharing M72.2), which matters for adolescent patients presenting with foot pain during sports seasons. The osteomyelitis codes in M86.8X expand by site and laterality, relevant for documenting conditions like frontal bone osteomyelitis in pediatric patients.
| Category | What Changed | Old Code | Pediatric Impact |
|---|---|---|---|
| Pyloric stenosis | New dedicated childhood code K31.B | Less specific K31 code | Matches clinical reality; higher specificity reduces audit risk |
| Plantar fasciitis | Separated from Ledderhose disease into M67.A by foot and laterality | M72.2 (shared code) | Adolescent sports medicine encounters coded more accurately |
| Osteomyelitis | M86.8X expanded by site and laterality | Less specific M86.8X | Better documentation for pediatric bone infections |
| Deleted codes | 30 codes inactive as of 10/1/2026 | See CMS conversion table | Claims using deleted codes reject automatically |
What Happens If Your Practice Does Not Update?
Claims submitted with a deleted ICD-10-CM code after October 1, 2026, will be rejected at the clearinghouse or denied by the payer. There is no grace period. The rejection reason will typically cite an invalid diagnosis code, and the claim must be corrected and resubmitted with the replacement code before it can process. In a high-volume pediatric practice billing hundreds of claims per week, even one deleted code embedded in a commonly used EHR template can generate dozens of rejections before someone identifies the root cause.
Providers often come to us after a wave of claim rejections that started on October 1 and did not get traced to a code set update for days or even weeks. The delay compounds: each rejected claim needs manual correction, the resubmission adds days to the payment cycle, and if the corrected claim misses a payer’s timely filing window, the revenue is lost permanently. The fix takes 30 minutes before October 1 or weeks of rework after it.
The conversion table published by CMS maps each deleted code to the replacement code or codes that should be used instead. Reviewing this table against your active EHR code sets is the single most important step in the annual update process, and it is the step most commonly skipped.
The October 1 ICD-10 cutover is two weeks away. If your team does not have time to audit every EHR template, superbill, and auto-population rule for deleted codes before the deadline, a billing partner who already tracks annual code set updates handles that transition as part of their standard workflow. Pediatrician Billers connects practices across all 50 states with rates starting as low as 2.95%.
How to Prepare Your Pediatric Practice Before October 1
The practices that avoid October 1 claim rejections follow the same preparation steps every year. These are the items to complete before the new code set goes live.
- Download the CMS conversion table. The FY 2027 conversion table identifies every inactive code and its replacement. Run the deleted code list against your EHR’s active diagnosis code set.
- Audit EHR templates and favorites lists. Check the diagnosis code pick lists in your most-used encounter templates, especially well-child visit, sick visit, and behavioral health templates. Any deleted code in a template will auto-populate onto claims.
- Update the superbill. If your practice uses a printed or digital superbill, confirm that every ICD-10 code on it is valid in the FY 2027 code set.
- Notify your billing team or billing company. If billing is handled externally, confirm that your partner has updated their claim scrubber and code validation rules for FY 2027.
- Add new codes where they apply. Review the 190 new codes for pediatric relevance. K31.B for pyloric stenosis should be added to your surgical and infant care templates now.
- Test a claim with the new codes in your staging environment. If your EHR supports a test claim function, submit one with a new FY 2027 code before October 1 to confirm your clearinghouse accepts it.
Common Mistakes During Code Set Transitions
Across the billing companies we vet for pediatric practices, the same handful of transition errors repeat every October. Treating these as process failures rather than one-off mistakes is what separates the practices that see zero impact from the ones that spend the first two weeks of October fixing preventable rejections.
The most common mistake is not running the deleted code list against EHR templates. Practices update their claim scrubber but forget that diagnosis codes auto-populate from encounter templates, favorites lists, and order sets. A code that is valid in the scrubber but deleted from ICD-10-CM still rejects at the payer level.
The second most common mistake is adding new codes without checking payer readiness. CMS updates its systems on October 1, but some commercial payers and state Medicaid programs take 30 to 60 days to load new codes into their adjudication systems. A claim submitted with a valid FY 2027 code that the payer has not yet loaded will be denied as an invalid code, not because the code is wrong but because the payer is not ready. The workaround is to check payer-specific guidance for the transition window and, where a payer lags, use the nearest valid predecessor code with documentation supporting the new code for resubmission after the payer updates.
For practices navigating the ICD-10 update alongside the 2027 Medicare payment changes and the proposed modifier 25 reduction, the administrative load of managing multiple concurrent changes is exactly the scenario where a specialized billing partner earns its fee.
In-House vs. a Billing Partner
Whether to handle the annual ICD-10 code set update in house or rely on a billing partner depends on whether your team has the bandwidth to audit, update, and test before October 1. A practice with a dedicated billing manager and a small, standardized template library may handle it efficiently. A multi-provider pediatric group with dozens of encounter templates, custom order sets, and a complex payer mix often finds that the billing partner catches the edge cases the in-house team misses.
In our experience matching pediatric practices with billing partners, the practices that absorb the least disruption from annual code transitions are the ones whose billing company proactively sends them a crosswalk of affected codes before the update takes effect, rather than waiting to fix rejections after October 1. That proactive approach is a reliable indicator of a billing partner that treats code compliance as a continuous process, not a once-a-year fire drill. For more on evaluating billing partners for your pediatric practice, see our guide on how to find the right pediatric medical billing service.
Frequently Asked Questions
The FY 2027 ICD-10-CM codes take effect October 1, 2026, and apply to all patient encounters and discharges from that date through September 30, 2027. There is no grace period for using deleted codes after September 30, 2026. Claims submitted with an inactive code will reject automatically.
The FY 2027 update includes 190 new codes, 30 deleted codes, and 4 revised code descriptions. The new codes span nearly every chapter of ICD-10-CM. The code files were released by CMS and the CDC’s National Center for Health Statistics in June 2026.
K31.B is a new ICD-10-CM code for hypertrophic pyloric stenosis in childhood. It provides pediatric coders with a dedicated code for a condition that was previously reported with a less specific, largely adult-oriented code from the K31 category.
The claim will be rejected at the clearinghouse or denied by the payer with a reason code citing an invalid diagnosis. The claim must be corrected with the replacement code and resubmitted. If the corrected claim misses the payer’s timely filing deadline, the revenue is lost.
CMS publishes a conversion table alongside the FY 2027 ICD-10-CM code files on the CMS ICD-10 page. The table maps each deleted code to its replacement. Download it, run it against your active code sets, and update your EHR templates before October 1.
Not always. CMS and Medicare update on October 1, but some commercial payers and state Medicaid programs take 30 to 60 days to load new codes. Check each payer’s transition guidance and plan for the possibility that a valid FY 2027 code may be temporarily rejected by a payer that has not updated its system yet.
Next Steps
Download the FY 2027 ICD-10-CM conversion table from the CMS website and run the deleted code list against your EHR templates, superbills, and favorites lists before October 1.
Add K31.B to your infant and surgical encounter templates now so it is available for pyloric stenosis documentation starting October 1.
If your team cannot complete the audit before the deadline, get matched with a pediatric billing partner who handles annual code set transitions as part of their standard workflow.
October 1 is two weeks away, and 30 deleted ICD-10 codes are about to start rejecting claims. If your practice does not have time to audit every template and update every code set before the cutover, a specialized billing partner handles that transition without missing a claim. Pediatrician Billers has connected more than 2,000 providers across all 50 states, with over 15 years in medical billing and rates starting as low as 2.95%. Finding a match is 100% free for providers.
