ICD-10-CM Changes Effective October 1, 2026: What Healthcare Practices Need to Know

The FY 2027 ICD-10-CM update introduces 190 new reportable diagnosis codes, invalidates 30 previously reportable codes, and revises four code descriptions. For healthcare practices, preparing for these changes means reviewing frequently used diagnoses, updating documentation templates, and checking that billing systems select codes appropriate to the date of service.

The changes affect a range of clinical areas, including cardiovascular disease, musculoskeletal conditions, women’s health, hereditary cancer syndromes, respiratory disease, and postprocedural complications.

This article highlights the major updates and practical steps practices can take before implementation.

The FY 2027 Update at a Glance

The combined 224 additions, invalidations, and description revisions do not represent every change. Practices must also consider updates to inclusion terms, exclusion notes, the Alphabetic Index, and sequencing instructions.

Some previously reportable codes remain in the classification as headings but now require additional characters. These headings cannot be submitted as complete diagnosis codes.

When Should Practices Start Using the New Codes?

For outpatient encounters, use the code set applicable to the date of service.

For example:

• A service provided on September 30, 2026, uses the code set applicable on that date, even if the claim is submitted in October.
• A service provided on October 1, 2026, uses the FY 2027 code set.
• A corrected claim for an earlier service date should not automatically be converted to the newest codes.

For hospital inpatient reporting, code-set applicability follows the discharge date. Practices should distinguish these settings when updating workflows.

Musculoskeletal and Rehabilitation Changes

Plantar fasciitis receives dedicated codes

One of the most practical changes for physical therapy, sports medicine, podiatry, chiropractic, and other practices treating foot conditions is the introduction of dedicated plantar fasciitis codes:

• M67.A01 — Plantar fasciitis, right foot
• M67.A02 — Plantar fasciitis, left foot
• M67.A09 — Plantar fasciitis, unspecified foot

Previously saved diagnosis selections that mapped plantar fasciitis to M72.2 need review.

Practice action: Document the affected foot and ensure the diagnosis selected in the EHR matches the clinical condition.

Plantar fascial fibromatosis gains laterality

Plantar fascial fibromatosis, also known as Ledderhose disease, now has separate laterality-specific codes:

• M72.20 — Plantar fascial fibromatosis, unspecified foot
• M72.21 — Plantar fascial fibromatosis, right foot
• M72.22 — Plantar fascial fibromatosis, left foot

M72.2 alone is no longer reportable.The appropriate replacement depends on whether the provider documents plantar fasciitis or plantar fascial fibromatosis, and which foot is affected.

An automatic replacement of every M72.2 entry with the same new code could create inaccurate claims.

Difficulty walking and unsteadiness: an important exclusion change

At R26.2 — Difficulty in walking, not elsewhere classified, the exclusion for R26.81 — Unsteadiness on feet changes from Excludes1 to Excludes2.

An Excludes2 note permits both conditions to be coded when both are present and otherwise meet reporting requirements. It does not require both codes on every encounter.

Practice action: For applicable PT and OT encounters, document the walking limitations and balance deficits being evaluated or treated. Update claim edits that automatically prohibit this code combination.

Osteomyelitis codes become more specific

The M86.8X1–M86.8X8 branches expand to provide additional anatomical and laterality detail.

Examples include:

• M86.8X41 — Other osteomyelitis, right hand
• M86.8X42 — Other osteomyelitis, left hand
• M86.8X71 — Other osteomyelitis, right ankle and foot
• M86.8X72 — Other osteomyelitis, left ankle and foot

These changes may affect orthopaedics, infectious disease, wound care, rehabilitation, and surgical practices.

Selected injury coding changes

The S23.420 sternoclavicular sprain branch, including its encounter-specific codes, is deleted. Practices using these codes should review the current Index and Tabular List to determine the appropriate replacement for the documented injury.

At S22, the instruction for associated spinal cord injury changes from “Code also” to “Code first, if applicable” for the specified S24 code families. This is a sequencing change that deserves attention in trauma and rehabilitation workflows.

Cardiovascular Changes

Expanded cardiomyopathy codes

I42.0 — Dilated cardiomyopathy expands into:

• I42.00 — Dilated cardiomyopathy, unspecified
• I42.01 — Familial-genetic dilated cardiomyopathy
• I42.09 — Other dilated cardiomyopathy

I42.8 — Other cardiomyopathies expands into:

• I42.81 — Arrhythmogenic cardiomyopathy
• I42.89 — Other cardiomyopathies, not elsewhere classified

I42.0 and I42.8 alone are no longer reportable.Primary care, internal medicine, and cardiology practices should review problem lists and recurring encounter templates. The selected subtype must be supported by the provider’s documentation.

New arrhythmia codes

The update introduces:

• I47.22 — Catecholaminergic polymorphic ventricular tachycardia
• I49.81 — Brugada syndrome
• 49.82 — Ventricular bigeminy
• I49.89 — Other specified cardiac arrhythmias, not elsewhere classified

I49.8 alone is no longer reportable.For ventricular bigeminy, the classification also includes an instruction to report associated symptoms when applicable.

Digestive, Metabolic, and Nutritional Changes

Moderate hepatic fibrosis receives a separate code

• K74.0A — Hepatic fibrosis, moderate fibrosis

This new code includes stage F2 fibrosis. The inclusion under K74.01 — Hepatic fibrosis, early fibrosis changes from stages F1 or F2 to stage F1.

Practice action: Review patients with documented F2 fibrosis who were previously assigned K74.01. The appropriate code now depends on the documented fibrosis stage.

Postprocedural hypoglycemia becomes more specific

New codes include:

• E89.830 — Post-bariatric hypoglycemia
• E89.838 — Other postprocedural hypoglycemia

The classification instructs users to add the hypoglycemia-level code when known.

These changes are relevant to bariatric surgery, endocrinology, internal medicine, and practices providing postoperative follow-up.

Low adult BMI codes expand

Z68.1 is replaced for reporting purposes by:

• Z68.18 — Body mass index 18.4 or less, adult
• Z68.19 — Body mass index 18.5–19.9, adult

BMI reporting requirements still apply. A low BMI measurement alone should not be used to infer a diagnosis of underweight or malnutrition.

New pelvic disease codes

New options include:

• K6A.01 — Prevesical abscess
• K6A.09 — Other pelvic abscess
• K6A.8 — Other diseases of the pelvis, not elsewhere classified

Relevant additional-code instructions address associated conditions and infectious agents.

Oncology, Genetics, and Hematology Changes

Hereditary cancer syndromes receive dedicated codes

New codes include:

• QA1.71 — Lynch syndrome
• QA1.790 — Familial cancer syndrome with pathogenic BRCA1 mutation
• QA1.791 — Familial cancer syndrome with pathogenic BRCA2 mutation
• QA1.792 — Li-Fraumeni syndrome
• QA1.798 — Other inherited neoplasm predisposition syndrome of multiple systems

These codes may be relevant to oncology, gastroenterology, genetics, gynecology, and primary care.

They should not be treated as blanket replacements for all cancer-susceptibility or family-history codes. Review instructions for reporting associated malignancy, personal cancer history, and genetic susceptibility.

Additional metastatic-site specificity

New codes identify secondary malignancies at selected sites:

• C78.31 — Secondary malignant neoplasm of larynx
• C78.32 — Secondary malignant neoplasm of pharynx
• C79.83 — Secondary malignant neoplasm of oral cavity

Qualitative platelet defects expand

D69.1 becomes a heading requiring a more specific code:

• D69.11 — Glanzmann thrombasthenia
• D69.19 — Other qualitative platelet defects

Respiratory, ENT, and Infectious Disease Changes

Odontogenic sinusitis

New codes identify sinusitis of dental origin by the sinus involved:

• J34.830 — Maxillary sinus
• J34.831 — Ethmoid sinus
• J34.832 — Frontal sinus
• J34.833 — Sphenoid sinus
• J34.839 — Unspecified

Documentation should support both the diagnosis and the anatomical site.

Pulmonary mycetoma

• J4B — Pulmonary mycetoma

The code includes pulmonary fungal ball. An associated infection should also be coded when known, following the classification instructions.

Personal history of C. difficile infection

• Z86.17 — Personal history of Clostridioides difficile infection

This distinguishes a past infection from current disease. It should not replace coding for an active or recurrent infection.

Women’s Health and Surgical Changes

Women’s health updates include expanded coding for interstitial, cesarean-scar, cervical, and cornual ectopic pregnancies as well as a new O31.4- branch for continuing pregnancy after vanishing twin syndrome.

Code selection may require details such as trimester, laterality, coexisting intrauterine pregnancy, or fetus identification, depending on the code family.

For breast and plastic surgery, new codes include:

• N99.860 — Intraoperative and postprocedural nipple ischemia
• N99.861 — Intraoperative and postprocedural nipple necrosis

Ambulatory surgical centres should review changes against their actual procedure mix. This ICD-10-CM update concerns diagnoses; it does not replace CPT/HCPCS procedure coding or establish new procedure coverage.

The Four Revised Code Descriptions

Three revised descriptions distinguish the back from the flank more clearly:

• L02.232: Carbuncle of back—now excludes both buttock and flank.
• L03.312: Cellulitis of back—now excludes both buttock and flank.
• L03.322: Acute lymphangitis of back—now excludes both buttock and flank.

The fourth corrects terminology:

• Z29.14: “Rabies immune globin” changes to “rabies immune globulin.”

A description revision can affect code selection even when the code itself remains valid. Source: FY 2027 addendum.

Coding Guideline Changes Also Matter

The official guidelines clarify several areas, including:

• Hypertensive heart disease involving one or more of the specified heart conditions.
• Associated hypertensive disease reporting in hypertensive crisis, includingI1A.
• Chapter 17 guidance covering genetic disorders through QA1.
• The distinction between family exposure to diethylstilbestrol and the patient’s own direct in-utero exposure.

A Practical Readiness Checklist

1. Review your most frequently used diagnoses.
Compare recent diagnosis utilisation against the changes. Prioritise invalidated codes and those frequently used in recurring visits.

2. Update saved selections and templates.
Review EHR favourites, encounter forms, problem-list mappings, and billing-system edits. Avoid automatic substitutions when clinical details determine the replacement.

3. Address documentation gaps.
Identify where providers need to document laterality, anatomical site, disease subtype, stage, or the relationship between a condition and a procedure.

4. Confirm software readiness.
Check that the EHR, practice management system, and billing workflow support the new code set while retaining the correct versions for older service dates.

5. Review affected claim edits.
Pay attention to changed exclusion and sequencing instructions, including the R26.2/R26.81 update.

6. Monitor early October claims.
Investigate recurring rejections promptly and distinguish code-validity problems from coverage, eligibility, authorisation, and medical-necessity issues.

The changes relevant to a practice depend on its patient population and diagnosis usage. Not every specialty has a dedicated new-code group, but shared diagnoses and instructional changes can still affect its claims.

Have Questions? Email Medryte’s Certified Coding Team

Medryte’s certified coders support healthcare practices across the United States with specialty-specific coding questions and practical implementation guidance.

Email coding@medryte.com with your specialty, the diagnosis codes involved, and your question.Our team will review and respond to each inquiry by email—no call is required.

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