2026 ICD-10-CM Diagnosis Code N21Calculus of lower urinary tract

ICD-10-CM Codes›N00–N99›N20-N23›N21

ICD-10-CM N21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N21 is a non-billable ICD-10-CM category code for calculus of lower urinary tract, so it cannot be submitted on claims. Use a more specific code from this category instead, such as N21.0, N21.1, N21.8, and N21.9.

Code Identity

ICD-10-CM Code
N21
Billable Status
No — Non-Billable Category
Code Describes
Calculus of lower urinary tract
Chapter
N20-N23
Urolithiasis

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN20-N23Urolithiasis
CategoryN21Calculus of lower urinary tract
This CodeN21Calculus of lower urinary tract

Specific Coding for Calculus of lower urinary tractOverview

Non-specific codes like N21 require more characters. Use one of these billable codes instead:

  • Use N21.0 for Calculus in bladder

  • Use N21.1 for Calculus in urethra

  • Use N21.8 for Other lower urinary tract calculus

  • Use N21.9 for Calculus of lower urinary tract, unspecified

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Includes

  • calculus of lower urinary tract with cystitis and urethritis

Patient EducationClinical

Bladder Diseases

The bladder is a hollow organ in your lower abdomen that stores urine. Many conditions can affect your bladder. Some common ones are:

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Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About N21Overview

Is N21 (Calculus of lower urinary tract) a billable code?

No. This is a category header that groups the codes for calculus of lower urinary tract, and headers cannot be submitted on claims. Claims for calculus of lower urinary tract need a more specific code from this category, such as N21.0, N21.1, and N21.8.