News and guides · October 14, 2026
ICD-10-CM FY2027 Update: 190 New Codes and What Coders Should Know
The FY2027 ICD-10-CM code set took effect October 1, 2026: 190 new codes, 30 deleted and 4 revised. Here are the changes most likely to show up in practice and on exams.
Key takeaways
- FY2027 ICD-10-CM applies to encounters from October 1, 2026 through September 30, 2027.
- The official CDC addenda list 190 additions, 30 deletions and 4 revisions (74,879 codes in total, up from 74,719).
- Several former codes became category headers that now need a more specific code, including dilated cardiomyopathy and other osteomyelitis.
- The Official Guidelines were updated at the same time; use the FY2027 version for anything coded on or after October 1.
The numbers
Every October 1 the ICD-10-CM code set changes. The FY2027 update, published by CDC/NCHS and CMS, adds 190 codes, deletes 30 and revises the titles of 4, according to the official addenda file. The total grows from 74,719 codes in FY2026 to 74,879 in FY2027.
A "deleted" code is not always gone. Often the old code becomes a category header and new, more specific codes are created underneath it. Reporting the old code after October 1 will be rejected as invalid, so check any code you use from habit.
Bigger specificity: codes that now need more characters
Dilated cardiomyopathy (I42.0) and other cardiomyopathies (I42.8) were expanded. Dilated cardiomyopathy is now split into unspecified (I42.00), familial-genetic (I42.01) and other (I42.09), and the "other" group gains arrhythmogenic cardiomyopathy (I42.81) and other cardiomyopathies not elsewhere classified (I42.89).
Other specified cardiac arrhythmias (I49.8) was expanded with Brugada syndrome (I49.81), ventricular bigeminy (I49.82) and other specified arrhythmias (I49.89).
Other osteomyelitis (M86.8X-) now needs laterality: the site codes for shoulder, upper arm, forearm, hand, thigh, lower leg, and ankle and foot were replaced by right, left and unspecified versions. Plantar fascial fibromatosis (M72.2) likewise gained right, left and unspecified foot codes.
Qualitative platelet defects (D69.1) now separates Glanzmann thrombasthenia (D69.11) from other defects (D69.19), and the adult BMI code for 19.9 or less (Z68.1) was replaced by two ranges: 18.4 or less (Z68.18) and 18.5–19.9 (Z68.19).
New clinical areas
Pregnancy coding gets the largest single block: 28 new codes for continuing pregnancy after vanishing twin syndrome, by trimester and fetus, plus 16 new codes for interstitial, cornual, cervical and cesarean scar ectopic pregnancy, each with or without a coexisting intrauterine pregnancy.
Toxic-effect coding expands for specific solvents and chemicals, including alkenes and cycloparaffins (category T52), hexamethylene diisocyanate (T59) and medetomidine (T65), each with the usual intent and 7th-character options.
Oncology adds secondary malignant neoplasm codes for the larynx (C78.31), pharynx (C78.32) and oral cavity (C79.83). Odontogenic sinusitis gets its own codes by sinus (J34.83-), and new codes describe inherited cancer-predisposition syndromes such as Lynch syndrome and familial BRCA1 and BRCA2 syndromes, plus Loeys-Dietz syndrome.
New Z codes record exposures such as gadolinium, burn pits in a war theater, Agent Orange and blast overpressure, which matter for occupational and military health records.
What it means for your exam prep
Certification exams test how you apply the conventions and guidelines more than whether you remember new codes, and AAPC lets you choose current or previous-year code books. Still, current books are recommended, and the habit of checking the Tabular List for a required 5th, 6th or 7th character is exactly what these changes reward.
All ICD-10-CM questions on this site are checked against the FY2027 code set. Practise the rules in our ICD-10-CM set, or read the plain-language study guide on the Official Guidelines.