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N64 ICD-10-CM Code: Other disorders of breast

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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Disorders of breast (N60-N65)

N64

Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidance

Other disorders of breast

Other disorders of breast

CMS-HCC V28

N/A

Not mapped

CMS-HCC V24

N/A

Not mapped

ACA/HHS

N/A

Not mapped

ESRD/PACE

N/A

Not mapped

RXHCC

N/A

Not mapped

Code Book Path

Official
N6Disorders of breast (N60-N65)
N64Other disorders of breast

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for N64 in this effective period.

Excludes 2

Official
  • mechanical complication of breast prosthesis and implant (T85.4-)

Related Child Codes

Official
N64.0Fissure and fistula of nipple
N64.1Fat necrosis of breast
N64.2Atrophy of breast
N64.3Galactorrhea not associated with childbirth
N64.4Mastodynia

Includes

Official

ICD-10-CM does not list Includes notes for N64 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for N64 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for N64 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for N64 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for N64 in this effective period.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Coder workflow notes

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What This Code Means

N64 is the ICD-10-CM diagnosis code for other disorders of breast. N64 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering disorders of breast (n60-n65).

Header codes like N64 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at N64's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N64 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Excludes 2, Not included here, may code separately

  • mechanical complication of breast prosthesis and implant (T85.4-)

Child Codes

Code Hierarchy

N64Other disorders of breast
N64Other disorders of breast

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