2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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
Short Description
Calculus of lower urinary tract
Same as the full description in the CMS dataset.
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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N21: its own notes plus those printed at Chapter 14. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

  • calculus of lower urinary tract with cystitis and urethritis

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 14 (N00-N99) Diseases of the genitourinary system applies to 838 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name N21, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming N21: its condition is not part of those codes, and both may be reported when the patient has both.

  • Block N25-N29 Other disorders of kidney and ureter
    disorders of kidney and ureter with urolithiasis (N20-N23) names N20-N23, which includes this code

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:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About N21Overview

What is the ICD-10 code for calculus of lower urinary tract?

N21 is the ICD-10-CM category for calculus of lower urinary tract, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

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.