New ICD-10 Codes for October 2026 (FY 2027): What Billing Teams Need to Know
The FY 2027 ICD-10-CM diagnosis code set is active as of October 1, 2026. Discover the 190 new billable codes, deleted categories, and key workflow updates required to prevent claim denials.
The FY 2027 ICD-10-CM diagnosis code set is now in effect. Per CMS, these codes apply to patient encounters and discharges from October 1, 2026 through September 30, 2027.
The annual update is more than a software refresh. New, revised, and non-billable codes can affect clinical documentation, EHR diagnosis searches, claim edits, medical necessity checks, coding workflows, and reimbursement. Using an outdated or non-billable diagnosis code for a FY 2027 service can result in claim edits or rejection.
FY 2027 ICD-10-CM at a Glance
| Update Metric | FY 2027 Detail |
|---|---|
| New billable diagnosis codes | 190 |
| Codes that stop being billable | 30 (15 deleted, 15 converted to non-billable headers) |
| Revised code descriptions | 4 |
| Effective date | October 1, 2026 |
| Code set period | October 1, 2026 – September 30, 2027 |
| Total billable ICD-10-CM codes | 74,879 |
Sources: CMS ICD-10 files, CDC National Center for Health Statistics (NCHS) ICD-10-CM files, and the FY 2027 addenda.
Which ICD-10-CM Code Set Applies?
The applicable code set depends on the date of service for outpatient services or the discharge date for inpatient services, not the date a claim is submitted.
| Date of Service / Discharge | Applicable Code Set |
|---|---|
| September 30, 2026 | FY 2026 ICD-10-CM |
| October 1, 2026 | FY 2027 ICD-10-CM |
| October 15, 2026 | FY 2027 ICD-10-CM |
| September 30, 2027 | FY 2027 ICD-10-CM |
A claim submitted in October 2026 for a September 2026 service still uses the applicable FY 2026 code set. Billing systems must retain historical code versions so the correct code can be reported for the applicable date of service or discharge.
ICD-10 Codes That Stop Being Billable on October 1
These changes are among the most likely to affect claim validation and diagnosis selection.
Deleted Codes
- S23.420A, S23.420D, and S23.420S: Sprain of the sternoclavicular joint or ligament, including the applicable encounter characters.
- T52.8X- codes: Toxic effects of other organic solvents. These are replaced by more specific code families, including T52.81- for alkenes, T52.82- for cycloparaffins, and T52.89- for other organic solvents.
Previously Billable Codes That Are Now Non-Billable Headers
Some FY 2026 codes remain in the classification as parent categories but can no longer be submitted as final billable diagnosis codes. The more specific child code should be selected when supported by documentation.
| FY 2026 Code | FY 2027 Change & Requirement |
|---|---|
| I42.0 Dilated cardiomyopathy | Use I42.00, I42.01, or I42.09 |
| I42.8 Other cardiomyopathies | Use I42.81 or I42.89 |
| I49.8 Other specified cardiac arrhythmias | Use I49.81, I49.82, or I49.89 |
| Z68.1 BMI 19.9 or less, adult | Use Z68.18 or Z68.19 |
| M72.2 Plantar fascial fibromatosis | Use M72.20, M72.21, or M72.22 |
| M86.8X1–M86.8X8 Other osteomyelitis by site | Use new site- and laterality-specific child codes |
| D69.1 Qualitative platelet defects | Use D69.11 or D69.19 |
What's New in the FY 2027 ICD-10-CM Code Set?
The FY 2027 update adds 190 new billable diagnosis codes, makes 30 codes no longer billable, and revises four code descriptions.
The changes add specificity across several areas of medicine, including cardiovascular conditions, oncology, BMI classification, sinusitis, musculoskeletal conditions, pregnancy, toxic effects, and genetic disorders.
Cardiovascular
- I49.81 Brugada syndrome
- I49.82 Ventricular bigeminy
- I47.22 Catecholaminergic polymorphic ventricular tachycardia (CPVT)
- I42.81 Arrhythmogenic cardiomyopathy
- I42.00 Dilated cardiomyopathy, unspecified
- I42.01 Familial-genetic dilated cardiomyopathy
- I42.09 Other dilated cardiomyopathy
Oncology
- C78.31 Secondary malignant neoplasm of larynx
- C78.32 Secondary malignant neoplasm of pharynx
- C79.83 Secondary malignant neoplasm of oral cavity
Body Mass Index (BMI)
The FY 2027 update expands the adult BMI category with more specific lower BMI ranges:
- Z68.18 Body mass index (BMI) 18.4 or less, adult
- Z68.19 Body mass index (BMI) 18.5–19.9, adult
Sinusitis
New codes provide greater specificity for odontogenic sinusitis:
- J34.830 Odontogenic sinusitis, maxillary sinus
- J34.831 Odontogenic sinusitis, ethmoid sinus
- J34.832 Odontogenic sinusitis, frontal sinus
- J34.833 Odontogenic sinusitis, sphenoid sinus
- J34.839 Odontogenic sinusitis, unspecified
Musculoskeletal and Foot
Adds greater specificity for plantar fasciitis and plantar fascial fibromatosis:
- M67.A01 Plantar fasciitis, right foot
- M67.A02 Plantar fasciitis, left foot
- M67.A09 Plantar fasciitis, unspecified foot
- M72.20 Plantar fascial fibromatosis, unspecified foot
- M72.21 Plantar fascial fibromatosis, right foot
- M72.22 Plantar fascial fibromatosis, left foot
- M04.3 VEXAS syndrome
Pregnancy
Adds greater specificity for ectopic pregnancy (Cesarean scar, cervical, cornual, interstitial) and continuing pregnancy after vanishing twin syndrome.
Toxic Effects
Provides expanded options for specific substances including Alkenes, Cycloparaffins, Hexamethylene diisocyanate, and Medetomidine.
Other Notable Additions
- K76.83 Intestinal failure-associated liver disease
- Q87.A Loeys-Dietz syndrome
- QA1.71 Lynch syndrome
Should Medical Practices Delete Old ICD-10-CM Codes?
No.
Older codes are still required for:
- Corrected claims and resubmissions
- Historical medical records and audits
- Payment reconciliation
- Services provided before October 1, 2026
Billing and EHR systems should manage code validity based on the applicable date of service or discharge. Systems should prevent outdated codes from being selected for new services while preserving historical codes for earlier claims.
What Medical Billing Teams Should Update for FY 2027
-
Update the ICD-10-CM Database
Load official FY 2027 ICD-10-CM files into your EHR, PM system, billing software, and coding tools. Review Tabular Lists, Alphabetic Index, Addenda, Conversion Tables, and Official Guidelines.
-
Review EHR Pick Lists & Superbills
Remove deleted codes and non-billable headers from active pick lists, order sets, specialty favorites, and superbills for services dated October 1, 2026 or later.
-
Update Claim-Scrubbing Rules
Configure automated claim edits to enforce FY 2027 validity, mandatory character lengths, laterality, age/sex restrictions, and medical necessity rules.
-
Test Clearinghouse & Payer Workflows
Submit test claims with dates of service before and after October 1, 2026, to verify that clearinghouse engines handle historical and current codes correctly.
-
Monitor Diagnosis-Related Rejections
Track rejection reports daily. A spike in invalid diagnosis code errors indicates that an internal pick list, scrubber, or vendor dictionary hasn't been updated.
-
Review Clinical Documentation
Train clinical teams on documentation requirements for newly specific codes (e.g., laterality in plantar fasciitis or specific subtypes of cardiomyopathy).
FY 2027 ICD-10-CM Billing Checklist
- Load official FY 2027 ICD-10-CM tables into billing systems
- Update EHR diagnosis searches, pick lists, and favorite lists
- Replace deleted S23.420 and T52.8X codes in workflows
- Replace non-billable headers (I42.0, I42.8, I49.8, Z68.1, M72.2, M86.8X-, D69.1) with child codes
- Preserve historical code sets for claims with dates of service prior to Oct 1, 2026
- Update claim-scrubber rules and medical necessity edits
- Review laterality, age, sex, and character requirements
- Run test claims through clearinghouses
- Monitor daily claim rejection reports for code validity errors
- Audit physician documentation for increased code specificity
- Confirm AI-assisted coding/billing tools utilize the FY 2027 code set
Frequently Asked Questions About FY 2027 ICD-10-CM
When did the FY 2027 ICD-10-CM codes take effect?
The FY 2027 ICD-10-CM code set took effect on October 1, 2026 and applies through September 30, 2027 for applicable patient encounters and discharges.
How many new ICD-10-CM codes were added for FY 2027?
The FY 2027 update includes 190 new billable diagnosis codes.
How many ICD-10-CM codes are no longer billable?
30 codes are no longer billable for FY 2027. The changes include 15 deleted codes and 15 codes that became non-billable headers requiring more specific child codes.
Which ICD-10-CM code set applies to an October 1, 2026 date of service?
The FY 2027 ICD-10-CM code set applies to an October 1, 2026 date of service. For inpatient services, the applicable code set is determined by the discharge date.
Should old ICD-10-CM codes be deleted from billing systems?
No. Historical codes may still be required for claims, records, audits, and other purposes associated with earlier dates of service. Billing systems should manage code validity according to the applicable date of service or discharge.
Does this article cover ICD-10-PCS?
No. ICD-10-PCS procedure codes are a separate code set. CMS says the FY 2027 ICD-10-PCS update applies to inpatient discharges from October 1, 2026 through March 31, 2027.
Official FY 2027 ICD-10-CM Resources
Medical practices, coders, and billing teams should rely on official CMS and CDC files:
Final Takeaway
The FY 2027 ICD-10-CM update is now active, and medical billing teams should treat October 1 as more than a routine software update. Review your EHR diagnosis lists, coding databases, claim-scrubbing rules, clearinghouse configuration, and documentation workflows against the FY 2027 code set.
The golden rule : Use the ICD-10-CM code set that applies to the patient's date of service or discharge, while preserving historical code versions for earlier services.
This is incredibly helpful! Saving this as a reference guide for our team, thanks for putting this together.
Very helpful and informative.
Very Informative. Thanks for sharing.
Really Helpful.
Great update for medical billers and coders. Keeping ICD-10 codes, EHR systems, and billing workflows updated is essential for accurate claims and compliance. Thanks for sharing these important changes!
Informative FY 2027 ICD-10-CM reference especially for the new cardiology and arrhythmia codes, along with oncology, BMI, and other specialty-specific updates.