N13.2 Hydronephrosis with renal and ureteral calculous obstruction

The ICD-10-CM code for Hydronephrosis with renal and ureteral calculous obstruction is N13.2 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

14: Diseases of the genitourinary system (N00-N99)

Section

N10-N16: Renal tubulo-interstitial diseases (N10-N16)

Category N13

23 codes (18 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to N13.2:

• Calculus, calculi, calculous › urinary (duct) (impacted) (passage) (tract) › with hydronephrosis
• Calculus, calculi, calculous › ureter (impacted) (recurrent) › with hydronephrosis
• Calculus, calculi, calculous › kidney (impacted) (multiple) (pelvis) (recurrent) (staghorn) › congenital › with hydronephrosis
• Calculus, calculi, calculous › kidney (impacted) (multiple) (pelvis) (recurrent) (staghorn) › with calculus, ureter › with hydronephrosis
• Hydronephrosis (atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC › with › obstruction (by) (of) › renal calculus
• Ureteritis › due to calculus › with calculus, kidney › with hydronephrosis
• Calculus, calculi, calculous › ureter (impacted) (recurrent) › with calculus, kidney › with hydronephrosis
• Hydronephrosis (atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC › with › obstruction (by) (of) › ureteral NEC › calculus

U.S. Hospital Utilization

• An estimated 105,460 U.S. inpatient stays in 2023 included N13.2 among the documented diagnoses.
• 63,255 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

CKD staging and code assignment (N18.-)

The ICD-10-CM classifies CKD based on severity. The severity of CKD is designated by stages 1-5. Stage 2, code N18.2, equates to mild CKD; stage 3, codes N18.30-N18.32, equate to moderate CKD; and stage 4, code N18.4, equates to severe CKD. Code N18.6, End stage renal disease (ESRD), is assigned when the provider has documented end- stage renal disease (ESRD).

CKD stage plus ESRD: assign N18.6 only

If both a stage of CKD and ESRD are documented, assign code N18.6 only.

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)