FY 2027 ICD-10-CM Code Updates: New, Deleted, and Revised Codes Effective October 1, 2026

The Centers for Medicare & Medicaid Services (CMS) has officially released the fiscal year (FY) 2027 ICD-10-CM code set, introducing significant updates that every medical coder, clinical documentation specialist, and revenue cycle professional must understand before the October 1, 2026 implementation date.

This update includes 190 new codes, 30 deleted codes, and 4 revised codes — representing one of the more substantive annual revisions to the ICD-10-CM classification system. These codes apply to all patient discharges and outpatient encounters occurring from October 1, 2026 through September 30, 2027. 

Overview of FY 2027 ICD-10-CM Changes

Key New ICD-10-CM Codes for FY 2027

1. Vanishing Twin Syndrome — Category O31.4 (33 New Codes)

One of the largest additions in this update is a dedicated set of 33 new codes under category O31.4 for continuing pregnancy following vanishing twin syndrome. This addition reflects growing clinical recognition of this obstetric condition, in which one fetus in a multi-fetal pregnancy is reabsorbed early in gestation. Coders managing maternal-fetal medicine or obstetric cases should familiarize themselves with this expanded category to ensure precise documentation.

2. Toxic Effects of Cycloparaffins — Category T52.82 (17 New Codes)

A new subcategory of 17 codes under T52.82 captures the toxic effects of cycloparaffins — a class of saturated cyclic hydrocarbons. Similar in structure to the alkene codes described below, these codes include the standard encounter designations:

• A — Initial encounter
• D — Subsequent encounter
• S — Sequela

3. Secondary Malignant Neoplasms — New Site-Specific Codes

Three new codes expand coding specificity for secondary (metastatic) malignancies to sites not previously distinguished in the classification:

These additions are significant for oncology coders, as they allow for greater specificity when documenting metastatic disease in head and neck regions — an area frequently involved in the spread of primary malignancies.

4. Diseases of the Pelvis — New Category K6A

A brand new category, K6A, has been established for diseases of the pelvis not elsewhere classified. This fills a long-standing gap in the classification and is particularly relevant for coders in general surgery, gynecology, and urology settings.

5. Odontogenic Sinusitis — Category J34.83

The FY 2027 update introduces dedicated codes for odontogenic sinusitis, a type of sinusitis caused by dental infection or pathology. Previously coded as unspecified sinusitis, these new codes now allow documentation by specific sinus involved:

This is a meaningful advancement for ENT and dental-medical coding, enabling more accurate capture of the etiology and anatomical location of sinus disease.

6. Plantar Fasciitis — New Category M67.A and Expanded M72.2x

The FY 2027 update gives plantar fasciitis its own dedicated ICD-10-CM code category, ending years of coding under nonspecific soft tissue disorder codes. Laterality is now specified:

Plantar Fasciitis (M67.A):

Plantar Fascial Fibromatosis (M72.2x) — Laterality Expanded:

These codes are highly relevant for orthopedic, podiatry, and physical medicine coders, and will have direct downstream effects on MS-DRG assignment and outpatient APC grouping.

7. Toxic Effects of Alkenes — Category T52.81

A full set of 16 new codes under T52.81 captures the toxic effect of alkenes, with full intent and encounter specificity:

Coders handling toxicology, emergency medicine, and occupational health cases should take note of these additions.

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8. Body Mass Index (BMI) — New Adult Low-Range Codes

Two new BMI codes address underweight adult patients, expanding the granularity at the lower end of the BMI scale:

These codes are relevant for nutritional assessments, malnutrition risk screening, and related clinical documentation across inpatient and outpatient settings.

9. Gender Identity and Transitioning — New and Expanded Codes

The FY 2027 update includes several new codes addressing gender identity, transitioning, and personal history of gender-related procedures or transitions. These codes support documentation in behavioral health, endocrinology, and surgical settings:

These codes provide important context for clinical documentation and are consistent with ICD-10-CM’s broader shift toward comprehensive personal history coding.

Deleted ICD-10-CM Codes for FY 2027

Sternoclavicular Sprain Codes — S23.420x (Deleted)

Four codes related to sternoclavicular joint and ligament sprains are being deleted from the FY 2027 code set:

Coders should update their encoder systems and internal coding resources to reflect these deletions and identify appropriate alternative codes for documentation of sternoclavicular injuries going forward.

What Medical Coders Need to Do Before October 1, 2026

With the FY 2027 ICD-10-CM effective date approaching, the following steps are recommended:

1. Update Encoder and EHR Systems Ensure that your coding software, electronic health record (EHR) system, and charge capture tools are updated to reflect the new, deleted, and revised codes prior to October 1, 2026.

2. Educate Clinical Documentation Teams Providers and clinical documentation improvement (CDI) specialists should be made aware of new code categories — especially plantar fasciitis, odontogenic sinusitis, pelvic disease, and gender identity history codes — so that physician documentation supports the required specificity.

3. Review Payer Policies Some payers may update their coverage and medical necessity policies in response to these new codes. Monitor payer bulletins for any changes tied to the FY 2027 ICD-10-CM update.

4. Audit High-Impact Areas Focus internal audits on the specialty areas most impacted: obstetrics (O31.4), oncology (C78/C79), orthopedics (M67.A), ENT (J34.83), and toxicology (T52.81/T52.82).

5. Remove Deleted Codes from Charge Masters Immediately retire S23.420 and its encounter-specific variants from charge description masters (CDMs) and coding reference tools.

Summary

The FY 2027 ICD-10-CM code set represents a meaningful expansion in clinical specificity across multiple specialties. From dedicated codes for plantar fasciitis and odontogenic sinusitis, to new categories for pelvic disease and vanishing twin syndrome, these updates reflect the evolving complexity of medical documentation and the ongoing effort to align coding with clinical reality.

Medical coders, CDI specialists, and revenue cycle professionals are encouraged to review the full code list on the official CMS ICD-10 page and begin preparation well ahead of the October 1, 2026 implementation date.