ICD-10-CM Changes 2027: All 238 New and 21 Deleted Codes

The FY2027 ICD-10-CM update adds 238 new codes and removes 21, effective October 1, 2026, per the official CMS FY2027 order file. The additions cluster in injury and poisoning (85), pregnancy and childbirth (56), and musculoskeletal (33). For risk adjustment coders the headline is not the count. It is where they landed: dilated cardiomyopathy, a set of inherited and arrhythmia conditions, and a new block of Z codes that change how history and exposure get captured.

This is the complete, code-by-code list, grouped by ICD-10-CM chapter, plus the deleted codes and the ones that were restructured rather than truly removed. Every code and description comes straight from the official CMS FY2027 files. Bookmark it: when CMS posts the FY2027 risk adjustment mappings, we will add the HCC impact below. For prior-year context, see our FY2026 ICD-10-CM guidelines recap and the April 2026 ICD-10-CM update.

*Source: the official CMS FY2027 ICD-10-CM files (2027 Code Descriptions in Tabular Order), via the CMS ICD-10 page. Effective for encounters October 1, 2026 through September 30, 2027. Counts reflect a direct diff of the FY2027 and FY2026 order files. Verify against the CMS files before relying on any code for billing.*

FY2027 ICD-10-CM changes at a glance, effective October 1, 2026

As of October 1, 2026, ICD-10-CM expands by a net 217 codes. The 238 additions cluster in Chapter 19 (85 codes, mostly toxic-effect expansions for organic solvents, alkenes, and cycloparaffins), Chapter 15 (56 codes, ectopic pregnancy site specificity and vanishing twin detail), Chapter 13 (33 codes, osteomyelitis by site and plantar fasciitis laterality), and Chapter 21 (17 new Z codes for exposure history and gender transition). Twenty-one codes are deleted outright. Beyond those, several previously billable codes were demoted to non-billable category headers, which is the change most likely to slip past a carried-forward code list.

The FY2027 changes that matter most for risk adjustment

What happens to I42.0 dilated cardiomyopathy on October 1, 2026?

Dilated cardiomyopathy is no longer one code. I42.0 stops being billable at the cutover and becomes a category header. You code instead to I42.00 (unspecified), I42.01 (familial-genetic), or I42.09 (other). I42.8 also becomes a header, splitting into I42.81 (arrhythmogenic cardiomyopathy) and I42.89. If your templates or problem lists carry I42.0 or I42.8, they stop validating on October 1. Cardiomyopathy carries risk weight under current models, so confirm the FY2027 HCC assignment for each child code when CMS posts the mapping. For the co-morbidity context, see our heart failure HCC coding guide.

New arrhythmia and inherited cardiac codes

I49.81 (Brugada syndrome), I49.82 (ventricular bigeminy), and I47.22 (catecholaminergic polymorphic ventricular tachycardia) carve out conditions that previously fell to less specific parents. I49.8 itself becomes a non-billable header on October 1. For how arrhythmia specificity affects capture, see our atrial fibrillation HCC coding guide.

Inherited cancer predisposition gets its own block

The new QA1 category adds Lynch syndrome (QA1.71), familial cancer syndrome with BRCA1 (QA1.790) or BRCA2 (QA1.791) mutation, and Li-Fraumeni syndrome (QA1.792). Loeys-Dietz syndrome (Q87.A) and VEXAS syndrome (M04.3) also get first-time discrete codes. These conditions drive screening and surveillance, so the documentation to support them tends to be in the chart.

Gender-related history codes

Z87.8901 through Z87.8909 capture social, medical, surgical, intersex-surgery, and unspecified gender transition history, with Z87.893 for detransition and F64.A for gender identity disorder in remission.

Exposure and history Z codes

Blast overpressure (Z77.40 through Z77.49), Agent Orange (Z77.33), burn pits in a war theater (Z77.32), and gadolinium exposure (Z77.013) paired with R78.72 (abnormal gadolinium level in blood). Z86.17 adds personal history of Clostridioides difficile infection. Z68.18 (BMI 18.4 or less) and Z68.19 (BMI 18.5 to 19.9) add low-end BMI specificity that matters for malnutrition and frailty documentation.

A note on HCC mappings, and why this page will change

Last reviewed June 2026. This section updates as soon as CMS publishes the FY2027 ICD-10 to CMS-HCC crosswalk.

CMS releases the new fiscal year code descriptions first and the risk adjustment crosswalk (ICD-10 to CMS-HCC under V28) later, usually closer to the payment year. As of this writing the FY2027 mappings are not published. We are not going to guess which new codes map to an HCC, because a wrong RAF assumption is worse than no assumption at all. The moment CMS posts the FY2027 mapping, we will add the HCC and RAF impact below and update the date on this page. If you want that mapping the day it drops, the ICD-10 to HCC tool tracks the same cycle. For the model context, see what changed in CMS-HCC V28.

Deleted and restructured FY2027 codes

Most of the 21 deleted codes were restructured, not retired. The sternoclavicular sprain family (S23.420 and its 7th-character siblings) and the organic-solvent toxic-effect family (T52.8X) were broken into more specific codes, which appear in the new-code lists below. Read the full deleted list as a find-and-replace task, not a cleanup. Separately, the billable-to-header demotions noted earlier (I42.0, I42.8, I49.8) are not on this list because the parent still exists, but they stop being codeable. A carried-forward code or a saved favorite is the usual way any of these slip through after October 1.

Complete list of new FY2027 ICD-10-CM codes

All 238 new codes, grouped by ICD-10-CM chapter. Codes tagged "category header" are non-billable and need an additional character. Always code to the highest level of specificity the record supports. (Source: the CMS FY2027 ICD-10-CM order file, effective October 1, 2026.)

Chapter 2. Neoplasms (3 new)

Chapter 3. Blood & Immune Disorders (2 new)

Chapter 4. Endocrine, Nutritional & Metabolic (3 new)

Chapter 5. Mental, Behavioral & Neurodevelopmental (1 new)

Chapter 9. Circulatory System (9 new)

Chapter 10. Respiratory System (7 new)

Chapter 11. Digestive System (8 new)

Chapter 12. Skin & Subcutaneous Tissue (1 new)

Chapter 13. Musculoskeletal & Connective Tissue (33 new)

Chapter 14. Genitourinary System (3 new)

Chapter 15. Pregnancy, Childbirth & the Puerperium (56 new)

Chapter 15 adds 56 codes, mostly ectopic pregnancy site specificity and vanishing twin syndrome detail. Obstetric coding sits outside Medicare Advantage risk adjustment, so these are included for completeness.

Chapter 17. Congenital Malformations (9 new)

Chapter 18. Symptoms, Signs & Abnormal Findings (1 new)

Chapter 19. Injury, Poisoning & External Causes (85 new)

Chapter 19 holds 85 of the 238 additions, almost entirely toxic-effect codes split from the deleted T52.8X family (alkenes, cycloparaffins, hexamethylene diisocyanate, and medetomidine). These are low-relevance for most risk adjustment work and are listed here for completeness.

Chapter 21. Factors Influencing Health Status (Z codes) (17 new)

How should coders prepare for the FY2027 cutover?

The codes are final. The risk adjustment mapping is the piece still to come, and we will update this page the day it lands.