FY 2027 ICD-10-CM Code Updates

The Center for Medicare and Medicaid Services has released the FY 2027 updates to the ICD-10-CM code classification. There are less than half as many new codes this year as compared to last year, with the number of codes being added to a single chapter ranging from 1 to 60.

This this table show the breakdown of code updates by chapter of ICD-10-CM.

ICD-10-CM Coding Guidelines

The updates to the ICD-10-CM Official Guidelines for Coding and Reporting are minimal for 2027. The updates include the addition of one new guideline as well as rewording of or additions to four existing guidelines.

This table summarizes the guidelines with updates. Each guideline should be reviewed with an eye towards any changes it brings to correct coding practices.

The hypertension guidelines in Chapter 9 are getting some minor wording changes.

The phrase “one or more” had been added to guideline I.C.9.a.1 – Hypertension with Heart Disease to specify that a code from category I11 Hypertensive heart disease is assigned for a patient who has one or more of the heart conditions for heart failure or other heart diseases listed in the guideline.

Additionally, the guideline for hypertensive crisis, I.C.9.a.10, was updated to add code I1A Resistant hypertension to the list of codes included in the “Code also” instruction in the guideline.

The title of Chapter 17 of ICD-10-CM is being updated with the addition of “genetic disorders” to the list of conditions whose codes are included in this chapter. Several updates were made to the guidelines for this chapter to include reference to genetic disorders.

A new code, Z84.A Family history of exposure to diethylstilbestrol was added to the list of family history Z codes included in the guidelines for Chapter 21. A note is included under this code explaining the circumstances under which this code is to be reported.

A note was also added to the guidelines for code Z91.B Personal risk factor of exposure to diethylstilbestrol specifying that this code is assigned when a patient had direct exposure to diethylstilbestrol while in utero.

ICD-10-CM Alphabetic Index

Most of the entries added to or deleted from the index are related to the addition of new codes or the addition of new inclusion terms being added under some codes. There are several instances though where the index has changed the code directed for use for a particular search of the index, which sometimes even reclassifies the diagnosis to a new chapter of ICD-10-CM, or added new search terms providing a way to locate a code but not due to the introduction of a new code.

Examples:

The diagnoses of De Morgan’s spots and cecal polyp have been reclassified in the Alphabetic Index to a whole different chapter of ICD-10-CM. For example, previously, a search of the terms Polyp, cecum led to a code for a benign neoplasm of cecum from Chapter 2, but the changes to the index for 2027 now direct the assignment of a code for polyp of the colon from Chapter 11 Diseases of the Digestive System.

New terms have been added leading to code R41.0, clarifying this as the default code for a diagnosis of acute confusion.

Subterms have been added to allow for reporting sinusitis of odontogenic origin.

ICD-10-CM Tabular List

The greatest number of updates to ICD-10-CM for 2027 were made within the Tabular List. Updates consist primarily of adding new codes or expanding existing codes to provider greater specificity, but there were also a notable number of updates to instructional notes, such as the addition of Excludes1 and Excludes2 notes, Code first, Code Also and Use Additional Code notes, and Excludes1 or Excludes2 notes being changed to the other type of Excludes note. When coders begin assigning codes on October 1, 2026, it is recommended to pay particular attention to reviewing any relevant instructional notes in the Tabular List for applicable changes.

Selected 2027 ICD-10-CM Updates

The list below highlights some of the significant 2027 updates to ICD-10-CM.

• Chapter 2: Neoplasms
  • Three new codes have been added to allow reporting of secondary malignancy of more specific respiratory sites.
    • C78.31 Secondary malignant neoplasm of larynx
    • C78.32 Secondary malignant neoplasm of pharynx
    • C79.83 Secondary malignant neoplasm of oral cavity
• Chapter 4: Endocrine, Nutritional and Metabolic Diseases
  • Two new codes have been added to allow reporting of postprocedural hypoglycemia following a procedure.
    • E89.830 Post bariatric hypoglycemia
    • E89.838 Other postprocedural hypoglycemia
  • These codes have a “Use Additional” code note for hypoglycemia level (E16.A-).
  • These codes are CCs for 2027
• Chapter 9: Diseases of the Circulatory System
  • Code I42.0 Dilated cardiomyopathy is being expanded into a subcategory to allow specific reporting of dilated cardiomyopathy due to genetics.
    • I42.00 Dilated cardiomyopathy, unspecified
    • I42.01 Familial-genetic dilated cardiomyopathy
    • I42.09 Other dilated cardiomyopathy
  • Code I42.8 Other cardiomyopathies is also being expanded into a subcategory to allow specific reporting of cardiomyopathy due to cardiac arrythmia.
    • I42.81 Arrhythmogenic cardiomyopathy
    • I42.89 Other cardiomyopathies not elsewhere classified
  • These 5 codes are CCs for 2027
• Chapter 10: Diseases of the Respiratory System
  • Codes have been added to allow reporting of sinusitis of odontogenic origin. Codes are available for odontogenic sinusitis of the following:
    • Maxillary sinus (J34.830)
    • Ethmoid sinus (J34.831)
    • Frontal sinus (J34.832)
    • Sphenoid sinus (J34.833)
    • Unspecified sinus (J34.839)
  • A new code is being added to report pulmonary mycetoma, J4B.
    • This code has an accompanying “Code also” note for associated infection (e.g., aspergillosis)
    • The infection codes (aspergillosis) have reciprocal “Code also” notes for J4B Pulmonary mycetoma
  • All these new codes are CCs for 2027
• Chapter 15: Pregnancy, Childbirth and the Puerperium
  • Several changes are being made in category O00 Ectopic pregnancy to include:
    • The addition of new subcategories to report ectopic pregnancy of:
      • Cesarean scar
      • Cervix
      • Cornua
    • Codes have been expanded at the 5^th character to specify with or without intrauterine pregnancy.
    • Where applicable, codes have 6^th characters to identify laterality.
  • Subcategory O31.4 has been added to report continuing pregnancy after vanishing twin syndrome of one fetus or more. These codes have a 5^th character to identify trimester.
• Chapter 21: Factors Influencing Health Status and Contact with Health Services
  • Code Z68.1 Body mass index [BMI] 19.9 or less, adult has been expanded at the 5^th character to create new codes:
    • Z68.18 Body mass index [BMI] 18.4 or less, adult
    • Z68.19 Body mass index [BMI] 18.5-19.9, adult
  • These new codes are CCs
    
    
  • New codes are being added to report
    • Contact with and (suspected) exposure to gadolinium (Z77.013)
    • Contact with and (suspected) exposure to war theater (Z77.3)
    • Contact with and (suspected) exposure to blast overpressure (Z77.4)
    • Personal history of Clostridioides difficile infection (Z86.17)
    • Personal history of social gender transition (Z87.8901)
    • Personal history of medical gender transition (Z87.8902)
    • Personal history of surgical gender transition (Z87.8903)
    • Personal history of intersex surgery (Z87.8904)
    • Personal history of unspecified gender transition (Z87.8909)
    • Personal history of gender detransition (Z87.893)
  • Note: The following Z codes are being removed from the CC list for 2027
    • Z59.00 Homelessness, unspecified
    • Z59.01 Sheltered homelessness
    • Z59.02 Unsheltered homelessness
    • Z59.10 Inadequate housing, unspecified
    • Z59.11 Inadequate housing environmental temperature
    • Z59.12 Inadequate housing utilities
    • Z59.19 Other inadequate housing
    • Z59.811 Housing instability, housed, with risk of homelessness
    • Z59.812 Housing instability, housed, homelessness in past 12 months
    • Z59.819 Housing instability, housed unspecified

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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.