2026 ICD-10-CM Diagnosis Code N20.1Calculus of ureter

ICD-10-CM Codes›N00–N99›N20-N23›N20

ICD-10-CM N20.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N20.1 is a billable ICD-10-CM diagnosis code for calculus of ureter. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 693 through 694. Coders also document this condition as complete obstruction of the urinary tract. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Calculus of urinary tract.

Code Identity

ICD-10-CM Code
N20.1
Billable Status
Yes — Valid for Submission
Code Describes
Calculus of ureter
Short Description
Calculus of ureter
Same as the full description in the CMS dataset.
Parent Code
N20
Calculus of kidney and ureter

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN20-N23Urolithiasis
CategoryN20Calculus of kidney and ureter
This CodeN20.1Calculus of ureter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Complete obstruction of the urinary tract
  • Occlusion of ureter
  • Occlusion of ureter due to calculus
  • Steinstrasse
  • Ureteral sludge
  • Ureteric stone
  • Ureteric stone of lower third of ureter

Tabular List NotesGuidance

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

Inclusion Terms

  • Calculus of the ureteropelvic junction
  • Ureteric stone

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Calculus, calculi, calculous
      • ureter (impacted) (recurrent)
    • Calculus, calculi, calculous
      • ureteropelvic junction
    • Ureteritis
      • due to calculus

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN005
Calculus of urinary tract
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Ureteral Disorders

Your kidneys make urine by filtering wastes and extra water from your blood. The urine travels from the kidneys to the bladder in two thin tubes called ureters.

Read the full article at MedlinePlus

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

Convert N20.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
592.1 Calculus of ureter
Approximate The match is approximate rather than exact.

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 N20.1Overview

Is N20.1 (Calculus of kidney and ureter) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report calculus of ureter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N20.1 group to?

When calculus of ureter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 693, 694, with relative weights from 0.7817 to 1.3445 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of N20.1?

Under the General Equivalence Mappings, calculus of ureter converts to ICD-9-CM 592.1 (calculus of ureter). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.