Which date of service uses the new ICD-10-CM codes?

Claims with a date of service on or after October 1, 2026 use the FY 2027 code set. Dates of service through September 30, 2026 use the prior set.

How many new codes are in the FY 2027 update?

Early reports gave different totals. The figures cited from CMS’s final inpatient rule are 190 new codes, 30 deletions and 4 revisions. Check the official CMS and CDC files for the exact list.

What happens if a claim uses a deleted code?

Payers can reject or deny it as an invalid diagnosis code. Update your code tables and superbills so staff do not select deleted codes.

FY 2027 ICD-10-CM Update: What Billers Should Do

The FY 2027 ICD-10-CM update took effect October 1, 2026 and applies to dates of service through September 30, 2027. Figures cited from CMS’s final rule are 190 new codes, 30 deleted codes and 4 revised descriptors, though some early reports cited higher totals, so verify against the official files.

By Bill For You RCM · Published October 23, 2026. Educational information, not legal, coding or tax advice. Rules change; confirm with CMS and each payer.

What changed

Some previously complete codes now need additional characters. Coding publications cite examples such as D69.1 and Z68.1 requiring a fifth character, so older versions are no longer valid.
New codes appear across chapters, with examples reported in musculoskeletal (for instance a first code for VEXAS syndrome and new codes for Ledderhose disease), sinus and liver conditions, and plantar fasciitis subcategories.
CMS also released the FY 2027 ICD-10-PCS update for inpatient procedures, effective for discharges from October 1, 2026.
Totals reported by different publications varied, so work from the official CMS and CDC files rather than summaries.

What to do this week

Update code tables in your EHR, practice management system and clearinghouse, and confirm the date logic uses October 1, 2026.
Refresh superbills and favorites lists so staff and providers see valid codes.
Review your top 50 diagnosis codes for deletions, expansions and new, more specific options.
Watch rejections and denials for invalid-diagnosis edits over the next several weeks and fix root causes quickly.
Train coders and providers on documentation that supports the more specific codes.
Check the official guidelines for FY 2027 when posted and review any changes in sequencing or reporting rules.

Pair this with our year-end billing checklist and the denial reduction guide.

Sources and where to verify

CMS: ICD-10 codes (FY 2027 files)
CDC National Center for Health Statistics ICD-10-CM files
AAPC and AHA Coding Clinic analyses for specialty-specific impact (some are member-only).

FY 2027 ICD-10-CM Update: What Billers Should Do Now