2026 ICD-10-CM Diagnosis Code N13.731Vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral

ICD-10-CM Codes›N00–N99›N10-N16›N13

ICD-10-CM N13.731
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N13.731 is a billable ICD-10-CM diagnosis code for vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 698 through 700. Coders also document this condition as secondary left vesicoureteral reflux grade 3. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Vesicoureteral reflux.

Code Identity

ICD-10-CM Code
N13.731
Billable Status
Yes — Valid for Submission
Code Describes
Vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral
Short Description
Vesicoureter-reflux w reflux nephrop w hydrourt, unil
Parent Code
N13.73
Vesicoureteral-reflux with reflux nephropathy with hydroureter

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN10-N16Renal tubulo-interstitial diseases
CategoryN13Obstructive and reflux uropathy
This CodeN13.731Vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Secondary left vesicoureteral reflux grade 3
  • Secondary left vesicoureteral reflux grade 4
  • Secondary left vesicoureteral reflux grade 5
  • Secondary right vesicoureteral reflux grade 3
  • Secondary right vesicoureteral reflux grade 4
  • Secondary right vesicoureteral reflux grade 5

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.

    • Reflux
      • vesicoureteral (with scarring)
        • with
          • nephropathy
            • with hydroureter
              • unilateral

Clinical ClassificationClinical

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

CCSR GEN011
Vesicoureteral reflux
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Kidney Diseases

You have two kidneys, each about the size of your fist. They are near the middle of your back, just below the rib cage. Inside each kidney there are about a million tiny structures called nephrons. They filter your blood. They remove wastes and extra water, which become urine. The urine flows through tubes called ureters.

Read the full article at MedlinePlus

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

Convert N13.731 to ICD-9-CMHistory

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

ICD-9-CM
593.71 Vscurt rflx npht uniltrl
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 2017–2023No changes
FY 2024RevisedCode revised
FY 2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About N13.731Overview

Is N13.731 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N13.731 group to?

When vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral is the principal diagnosis on an inpatient stay, it groups to MS-DRG 698, 699, 700, with relative weights from 0.6899 to 1.6544 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of N13.731?

Under the General Equivalence Mappings, vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral converts to ICD-9-CM 593.71 (vscurt rflx npht uniltrl). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.