N21

ICD-10Non-billable category

Calculus of lower urinary tract

Official ICD-10-CM descriptor (FY2026)

Calculus of lower urinary tract

N21 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.

Includes

calculus of lower urinary tract with cystitis and urethritis

More specific codes under N21

Where this code sits

Chapter: 14. Diseases of the genitourinary system (N00-N99)
Block: Urolithiasis (N20-N23)

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Source

ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.