ICD-10-CM 2026 Updates: 487 New Codes and What Your Coders Must Know
The FY2026 ICD-10-CM update added 487 new codes — nearly double last year — effective October 1, 2025. Here are the biggest changes, the chapters most affected, and how to update your practice before denials pile up.
Every October 1, the ICD-10-CM code set updates — and FY2026 was a big one. With 487 new codes (nearly double the prior year), coders who don't keep pace start generating rejections fast. Here's what changed, where it concentrated, and how to update your practice before it costs you.
- 487 new codes
- 38 revised codes
- 28 deleted codes
- ~2x the new codes added in FY2025
The 2026 numbers
The FY2026 update took effect October 1, 2025 and applies to all discharges and encounters from that date forward. The headline is volume: 487 new codes is a steep jump, and it concentrates in a handful of chapters that touch many specialties.
The biggest changes
- Chapter 12 — Skin: one of the largest updates, with 100+ new codes for non-pressure chronic ulcers, now classified by anatomical site and severity.
- Chapter 17 — Congenital malformations: substantial new specificity.
- Chapter 19 — Injury & poisoning: a large batch of new codes.
- Oncology: new specificity including a designation for inflammatory breast cancer, plus genetic-susceptibility codes.
Volume is the risk. When 487 codes shift at once, "unspecified" habits and stale superbills turn into denials overnight.
Why it matters for denials
Two failure modes hurt practices every October: billing a deleted code (instant rejection) and defaulting to unspecified codes when a more specific option now exists (lower reimbursement and payer scrutiny). Both are avoidable with a timely update pass and coder education. Clean, specific diagnosis coding is foundational to a high clean-claim rate — see our clean claim rate guide.
Your update checklist
- Load the FY2026 code set into your EHR and billing system.
- Update superbills, encounter forms, and EHR "favorites" lists.
- Retire deleted codes and map them to their replacements.
- Brief coders and providers on the high-impact chapters (skin, congenital, injury, oncology).
- Watch for new payer LCD/NCD policies tied to the new codes.
- Audit a sample of post-October claims for specificity and rejections.
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The bottom line
487 new codes is a lot of surface area for error. Load the update, refresh your superbills, retire deleted codes, and coach your team on the high-volume chapters — and the October transition becomes a non-event instead of a denial spike. Want a coding accuracy check? Start with a free billing audit, backed by professional medical coding.
Sources
Frequently asked questions
The FY2026 update includes 487 new, 28 deleted, and 38 revised diagnosis codes, effective October 1, 2025 — nearly double the number of new codes added in FY2025.
October 1, 2025. They apply to discharges and encounters from October 1, 2025 onward. Using a deleted or outdated code on or after that date will cause rejections.
Chapter 12 (skin) saw one of the largest updates, with over 100 new codes for non-pressure chronic ulcers classified by anatomical site and severity. Congenital malformations (Ch. 17) and injury/poisoning (Ch. 19) also expanded significantly, along with new specificity for conditions like inflammatory breast cancer.
Claims submitted with deleted or invalid codes after October 1, 2025 will be rejected or denied, delaying payment. Superbills, EHR favorites, and payer policies all need updating.
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