2026 ICD-10-CM Diagnosis Code N20.1Calculus of ureter
ICD-10-CM Codes›N00–N99›N20-N23›N20
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
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. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 43 closely related codes. 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
Code Classification
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
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
due to calculus N20.1
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
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Convert N20.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About N20.1Overview
What is the ICD-10 code for calculus of ureter?
The ICD-10-CM code for calculus of ureter is N20.1 (sometimes written as N201). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
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.
Is N20.1 a CC or MCC?
CMS lists N20.1 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 43 closely related codes in its exclusion list.
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.
