ICD-10-CM FY2027 Is Live: 9 Code Changes to Check Before Your Next Claim Batch

By Elizaveta Bannova, Billing Department, WCH

It took effect a week ago. If an outdated code is still sitting in your favorites, your next claim may expose it.

Somewhere in your EHR, a physician’s favorites list still holds I42.0, a dilated cardiomyopathy code that is no longer billable as of October 1. It looks fine. It autocompletes. It can still trigger a claim edit.

That’s the quiet danger of this year’s update. It isn’t huge, but it’s pointed. CMS released the FY2027 code files with 190 new, 30 deleted, and 4 revised codes, with some of the changes turning formerly billable entries into non-billable headings. The changes land on familiar diagnoses where coders tend to work on autopilot.

The Short Version

The set is live for encounters and discharges from October 1, 2026 through September 30, 2027, per CMS.
Specificity is the theme. Site, side, subtype, stage, and procedure relationship now decide the code.
Invalid or non-billable codes are the fastest route to a claim edit. Parent headings that used to be billable now need a child code.
The encounter or discharge date decides, not the submission date. September encounters and discharges use the FY2026 files even if the claim is submitted later.
About the “30 deleted” figure. One breakdown of the CMS order file shows 15 billable codes removed outright and another 15 retained as non-billable headings. The operational takeaway is the same: formerly billable entries that are now deleted or non-billable should not be reported on claims.

The Nine changes Worth Your First Week

1. Dilated cardiomyopathy

I42.0 is no longer billable. In its place, the FY2027 code set provides I42.00 (unspecified), I42.01 (familial-genetic), and I42.09 (other). Update favorites and encoder mappings first.

Documentation tip: a positive genetic test alone doesn’t make it familial-genetic. The provider has to document that link.

2. Plantar fasciitis

New codes split by foot: M67.A01 (right), M67.A02 (left), M67.A09 (unspecified).

M72.2 also becomes a non-billable heading. For plantar fascial fibromatosis, use M72.20 for unspecified foot, M72.21 for right foot, or M72.22 for left foot.

Before this update, plantar fasciitis was an inclusion term under M72.2. Older mappings were not necessarily incorrect for their original dates of service. The FY2027 addenda remove that inclusion term and introduce the separate fasciitis family. Review any current mappings that still point fasciitis to M72.2.

Documentation tip: heel pain doesn’t make the two interchangeable. The provider’s stated diagnosis decides.

3. Other osteomyelitis (M86.8X-)

Several M86.8X subcategories are no longer billable on their own. They now lead to more specific right-, left-, and unspecified-site codes, for example M86.8X11, M86.8X12, and M86.8X19 for the shoulder. Orthopedic and podiatry claims are among the places to check first.

Coding tip: the added final digit here denotes laterality, so don’t assume it’s an A/D/S encounter character. Apply only what the Tabular List requires.

4. Secondary malignant neoplasms

New site-specific metastatic codes include C78.31 (larynx), C78.32 (pharynx), and C79.83 (oral cavity). If the documentation identifies a specific metastatic site, don’t default to a generic secondary-neoplasm code. Check the new site-specific options in the FY2027 Tabular List.

5. Breast cancer vs. carcinoma in situ

The Excludes note relationship between C50.- and D05.- changed in FY2027: the instruction under D05.- is now Excludes1 rather than Excludes2. Don’t automatically report a D05.- code together with a C50.- code. The general Excludes1 exception permits reporting both conditions when they are unrelated. Query the provider when that relationship is unclear. Read the current Tabular List rather than relying on an old encoder rule or last year’s habit.

Also new: the N99.86- subcategory for [exact title from the Tabular List, e.g. a specific type of postprocedural breast complication].

6. Postprocedural hypoglycemia

E89.830 (post-bariatric) and E89.838 (other postprocedural). E89.83 is a parent, not a claim code. E89.83 carries an instruction to use an additional E16.A- code for the hypoglycemia level if known. Report the supported level code when known; do not invent one to satisfy a payer edit.

Documentation tip: a surgery in the history isn’t a documented cause. The provider needs to state the relationship.

7. Carbuncle of the flank

L02.237 is new. The back carbuncle, cellulitis, and lymphangitis titles were revised to exclude the flank, which now has its own site-specific code. A carbuncle documented specifically as being on the flank should not be coded to the back carbuncle code L02.232.

8. Vanishing twin

O31.4-: continuing pregnancy after vanishing twin syndrome. The new family adds trimester- and fetus-specific choices, with the required seventh character identifying the fetus when applicable.

9. The niche-but-real ones

D69.11 (Glanzmann thrombasthenia)
K74.0A (moderate hepatic fibrosis): captures moderate/F2 fibrosis. K74.01 no longer includes F2 and retains early/F1 fibrosis, so check old mappings.
M04.3 (VEXAS syndrome): carries a “Code also any associated conditions” instruction.
J34.83- (odontogenic sinusitis): J34.830, J34.831, J34.832, J34.833, and J34.839.

These are easy to miss because they sit outside the high-volume diagnoses most practices review routinely.

Documentation tip: a raw FibroScan number or a gene mutation isn’t a diagnosis. Code from the provider’s interpretation.

What to Ask Your Providers For

Most of this update comes down to five details in the note:

Exact site (which organ, which part of the body)
Laterality (right, left, or genuinely unspecified)
Subtype or type (familial vs. other, invasive vs. in situ, fasciitis vs. fibromatosis)
Stage or severity (moderate fibrosis, for example)
Relationship to a procedure (stated, not implied)
If one is missing and it changes the code, query. Don’t infer.

Test Yourself

1. A note documents a secondary malignant neoplasm of the pharynx. Is a generic secondary-neoplasm code the best choice?
No. FY2027 adds C78.32 specifically for secondary malignant neoplasm of the pharynx. Verify the complete code and Tabular instructions before reporting it.

2. Pathology says carcinoma in situ, but the operative title reads “breast cancer resection.” Can you report an invasive C50.- code?
No. A procedure title doesn’t establish invasive disease. The documented diagnosis governs, and the Tabular’s current Excludes1 note, including its exception for unrelated conditions, guides any pairing of C50.- and D05.-.

3. An outpatient note says hypoglycemia is “likely related” to a gastric bypass two years ago. Can you assign E89.830?
Not as written. Outpatient “likely” can’t be coded as confirmed, and a surgical history alone doesn’t establish the link. Query the provider.

4. A rheumatology note confirms VEXAS syndrome. Symptom codes or M04.3?
M04.3. The confirmed diagnosis has its own code, and the code carries a “Code also any associated conditions” instruction.

5. Forty-five orthopedic and podiatry claims are rejected on October 12 with an “invalid or non-billable code” edit. Likely cause?
Old pre-FY2027 codes still mapped in favorites or the encoder, such as osteomyelitis headings that are no longer billable or plantar fasciitis still mapped to M72.2. Fix the mapping to the new laterality-based code. Don’t append A/D/S to a code unless the Tabular List actually requires a seventh character.

Bonus. A clinic gets 30 rejections on E89.838 claims with the edit “required secondary code missing.” The Tabular instructions can call for an additional hypoglycemia-level code (E16.A-) if applicable. Add one only when it’s supported and the instruction applies. Don’t invent a code to satisfy an edit.

Your First-Week Triage

Confirm the FY2027 code files are active in your EHR, encoder, clearinghouse, and audit tools, and keep older versions for earlier dates of service.
Purge deleted and non-billable codes from favorites, order sets, and templates. Start with cardiology, orthopedics, and podiatry.
Run your top diagnoses through claim validation end to end.
Pull the rejection report and look for invalid-code and missing-associated-code edits.
Watch unspecified-code usage. A spike in unspecified-code use warrants review of documentation, coder selection, and system mappings.
Remember coverage isn’t automatic. A valid new code doesn’t establish medical necessity or raise payment.

Get the Official Files

CMS hosts the FY2027 diagnosis files, including the Tabular and Index, Addendum, Conversion Table, POA Exempt Codes, and the FY2027 Coding Guidelines, at cms.gov/medicare/coding-billing/icd-10-codes. The CDC’s National Center for Health Statistics (NCHS) maintains and updates ICD-10-CM. Procedure codes (ICD-10-PCS) run on a different clock: the FY2027 files apply to discharges from October 1, 2026 through March 31, 2027.

Stuck on a specific scenario? CMS points coding questions to the AHA Coding Clinic Advisor, and Medicare claims-processing and payment questions to your Medicare Administrative Contractor (MAC).

This article is educational and not a substitute for the official Tabular List, guidelines, or payer policy. Always verify the complete code against the FY2027 files.

Sources

CMS, ICD-10 page (files, effective dates, guidelines): cms.gov/medicare/coding-billing/icd-10-codes
CMS/NCHS, FY2027 ICD-10-CM Official Guidelines: cms.gov/files/document/fy-2027-icd-10-cm-coding-guidelines.pdf
CDC/NCHS, ICD-10-CM files: cdc.gov/nchs/icd/icd-10-cm/files.html
AAPC webinar, Overview of the ICD-10 Updates for 2027 (Dawn Carter, Sept. 10, 2026)
AAPACN, FY2027 ICD-10-CM changes (new metastatic codes): aapacn.org/type/article/aapacn-advocacy-shapes-fy-2027-icd-10-cm-changes
HCC Buddy, FY2027 order-file breakdown: hccbuddy.com/blog/fy-2027-icd-10-cm-code-changes
SIR, “CMS releases new ICD-10-CM codes”: sirweb.org/publications/news/cms-releases-new-icd-10-cm-codes
ACDIS, FY2027 code set released: acdis.org/articles/news-icd-10-cm-code-set-fiscal-year-2027-released

icdlist.com/resources/icd-10-cm-updates