ICD-10-CM Code Updates - April 1, 2026

CMS and the CDC have released the updates to the ICD-10-CM classification, as well as an update to the grouper (V43.1), that become effective on April 1, 2026. This Coding Tip covers the updates to the classification including additions, deletions and changes made in the Alphabetic Index, Tabular List and Official Guidelines for Coding and Reporting.

Where can I find the updates?

To download the updated files, use this link to the CMS ICD-10 website https://www.cms.gov/medicare/coding-billing/icd-10-codes. The files include an updated version of the guidelines, the index and the tabular as well as an addendum with files that include only the specific changes being made to the classification. Reviewing the addendum makes it easy to see exactly what is being changed/updated.

ICD-10-CM Updates

There are no new diagnosis codes being implemented in the April 1, 2026, release of ICD-10-CM updates, but there are additions, deletions, and revisions to some index entries, tabular entries and instructional notes that have implications for the coding process.

Shown here is a summarization of the updates by section of ICD-10-CM.

Index to Diseases and Injuries

The are 4 alphabetic sections of the ICD-10-CM Index to Diseases and Injuries that have updates for April 1, 2026.

D

• The spelling of the term know was changed to known in the phrase, “other known condition” under the main term Drip, postnasal and the subterm “due to”.

P

• A new subterm, Parkinson’s disease – see Disease, Parkinson’s , was added under the main term Parkinsonism and new subterm due to.
• The main term Parkinson’s disease, syndrome or tremor – seen Parkinsonism was deleted and replaced with two new main terms, Parkinson’s disease – See Diseases, Parkinson’s and Parkinson’s syndrome or tremor – see Parkinsonism.

Note: This is a significant update because a diagnosis of Parkinson’s disease will now be directed by the Alphabetic index to code G20.A1 rather than G20.C.

• The spelling of the term know was changed to known in the phrase, “other known condition” under the main term Postnasal drip.

S

• The subterm pancytopenia was added under the main term Syndrome and the subterms myelodysplastic and with.   

T

• The code directed for use by a search of the index under the terms Tumor and neuroendocrine was changed from D3A.8 Other benign neuroendocrine tumors to C7A.- Malignant neuroendocrine tumors.  

Note: This is a significant update as codes in category C7A are CCs. The change to C7A.- for reporting neuroendocrine tumors rather than D3A.8 will result in gaining a CC.

Tabular List of Diseases and Injuries

The are 14 chapters in the ICD-10-CM Tabular List that have updates for April 1, 2026.  

Chapter 2 Neoplasms (C00-D49)

• The Excludes1 note that excluded codes for benign neoplasm of glomus jugulare D35.6, nevi from subcategories D22.- and the code for vascular nevus Q82.5 from being reported with codes from category D18 Hemangioma and lymphangioma, any site was changed to an Excludes2 note.
• The Excludes1 note that excluded codes for neoplasms of uncertain behavior (D37-D44, D48) from being reported with codes from category D49 Neoplasms of unspecified behavior was changed to an Excludes2 note.

Chapter 3 Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)

• The Excludes1 note that excluded code E53.8 Vitamin B12 deficiency from being reported with codes in category B51 Vitamin B12 deficiency anemia was deleted and an Excludes2 note for codes in category E53 Deficiency of other B group vitamins was added.
• The Excludes1 note that excluded codes from category D70 Neutropenia from being reported with codes in category D72 Other disorders of white blood cells was changed to an Excludes2 note
• The Excludes1 note that excluded codes for abortion or ectopic or molar pregnancy (O00-O07, O08.1) from being reported with codes in category D65 Disseminated intravascular coagulation [defibrination syndrome] was changed to an Excludes2 note.
• An Excludes1 note for D70.9 Malignant leukopenia was added under code D72.819 Decreased white blood cell count.

Chapter 4 Endocrine, nutritional and metabolic diseases (E00-E89)

• The Excludes1 note that excluded code E83.52 Familial hypocalciuric hypercalcemia from being reported with code E21.2 Other hyperparathyroidism was changed to an Excludes2 note.
• The Excludes1 note that excluded codes in category D51.- Vitamin B12 deficiency anemia from being reported with code E53.8 Deficiency of other B group vitamins was changed to an Excludes2 note.

Chapter 5 Mental, behavioral and neurodevelopmental disorders (F01-E99)

• A Code also, if applicable, sequela of concussion (S06.0X- with seventh character S) instructional note was added under code F07.81 Postconcussional syndrome.
• The Excludes1 note under F07.81 Postconcussional syndrome was expanded to include S06.0X- with seventh character A.

Chapter 6 Diseases of the nervous system (G00-G99)

• The Excludes1 note that excluded codes in category H46 Optic neuritis from being reported with code G36.0 Neuromyelitis optica [Devic] was changed to an Excludes2 note.
• Exclude1 was changed to Excludes1 under code G35.A Relapsing-remitting multiple sclerosis.
• The Excludes1 note that excluded code R51.9 Headache NOS from being reported with codes from category G43 Migraine was changed to an Excludes2 note.

Chapter 7 Diseases of the eye and adnexa (H00-H59)

• The Code first instructional note under code H40.84 Neovascular secondary angle closure glaucoma was changed to a Code also instructional note.

Chapter 9 Diseases of the circulatory system (I00-I59)

• The Excludes1 note for codes I35.- aortic valve disease not specified as rheumatic and I08.- aortic valve disease with mitral and/or tricuspid valve involvement under category I06 Rheumatic aortic valve diseases was changed to an Excludes2 note.
• The Use Additional code instructional note under subcategory I16.1 Hypertensive Emergency was changed to a Code also instructional note.
• Code for Fontan associated protein-losing enteropathy was changed from K90.89 Other intestinal malabsorption to K90.49 Malabsorption due to intolerance, NEC in the Code also note under code I27.841 Fontan-associated lymphatic dysfunction

Chapter 10 Diseases of the respiratory system (J00-J99)

• The Excludes1 note that excluded codes in category J96.- Respiratory failure, not elsewhere classified from being reported with code J95.82 Postprocedural respiratory failure was changed to an Excludes2 note.

Chapter 11 Diseases of the digestive system (K00-K95)

• The Excludes1 note that excluded codes in category K61.- Fissure and fistula of anal and rectal regions with abscess or cellulitis under category K60 Fissure and fistula of anal and rectal regions has been deleted.  

Chapter 14 Diseases of the genitourinary system (N00-N99)

• A Use Additional code, if applicable, to identify associated cachexia (E88.A) instructional note was added under category N18 Chronic kidney disease (CKD).

Chapter 17 Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)

• The title of Chapter 17 has been changed from  Congenital malformations, deformations, chromosomal abnormalities and genetic disorders (Q00-QA0) back to Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)

Chapter 18 Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)

• The Excludes1 note that excluded code R10.13 Dypepsia NOS from being reported with codes from category R12 Heartburn was changed to an Excludes2 note.
• The inclusion terms under codes in subcategory R92.3 Mammographic density found on imaging of breast have been updated. The inclusion terms have been updated to say, “Breast density category within Imaging Reporting and Data System (BI-RADS): A, B, C or D” and the inclusion terms, “Breast Imaging Reporting and Data System (BI-RADS): 1, 2, 3 or 4” have been deleted.

Chapter 19 Injury, poisoning and certain other consequences of external causes (S00-T88)

• The Excludes1 note that excluded codes for poisoning by, adverse effect of and underdosing of appetite depressants (T50.5-), antiepileptic, sedative- hypnotic and antiparkinsonism drugs (T42.3-, 4-, 6-) and psychodysleptics (T40.7-T40.9-) from being reported with codes from category T43 Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified was changed to an Excludes2 note.
• An instructional note for “Code also” if applicable, place of occurrence was added under code block T66-T78 Other and unspecified effects of external causes.

Chapter 21 Factors influencing health status and contact with health services (Z00-Z99)

• The Excludes1 note that excluded codes F11.9- Methadone use NOS and F11.2- Use of methadone for treatment of heroin addiction from being reported with code Z79.891 Long term (current) use of opiate analgesic was changed to an Excludes2 note.

Coding Considerations

In the cases where an Excludes1 note was changed to an Excludes2 note, if the patient has both the condition listed in the code with the note and the excluded code, it is now appropriate to report codes for both conditions if they are not integral to one another and meet the criteria for reporting.

Updates to the instructional notes that change “Code first” and “Use Additional code” notes to “Code also” notes have implications for sequencing. Previously, the notes that were changed directed sequencing of the codes associated with the note. A change to the “Code also” note means that sequencing now depends on the circumstances of admission. 

Coders should carefully review the updates to determine how the changes may impact their regular sequencing practices.

Example

Based on the “Code first” note under H40.84, if a patient has neovascular second angle closure glaucoma due to diabetes, the diabetes code from Chapter 3 was automatically sequenced first. After April 1, 2026, the coder will have to review the encounter to determine if the diabetes code or the secondary glaucoma code should be sequenced first, based on the circumstances of the encounter.

Example

Based on the “Use Additional code” note under subcategory I16.1, if a patient has organ dysfunction, such as a cerebral infarction, due to hypertensive emergency, the organ dysfunction code was automatically sequenced second. After April 1, 2026, the coder will have to review the encounter to determine if hypertensive emergency or organ dysfunction should be sequenced first, based on the circumstances of the encounter.

Official Guidelines for Coding and Reporting

Currently there are no updates to the ICD-10-CM Official Guidelines for Coding and Reporting for release on April 1, 2026.

We recommend all coders download the complete set of addenda files from the CMS.gov website listed below to have a complete copy of the changes/updates going into effect on April 1, 2026, to use as a reference when coding.

References

• https://www.cms.gov/medicare/coding-billing/icd-10-codes 

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The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.