N11.1 Chronic obstructive pyelonephritis
The ICD-10-CM code for Chronic obstructive pyelonephritis is N11.1 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- N10-N16: Renal tubulo-interstitial diseases (N10-N16)
- Category N11
- 5 codes (4 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to N11.1:
- Pyelonephrosis (obstructive)
- Obstruction, obstructed, obstructive › pyelonephritis (chronic)
- Pyelonephritis › in (due to) › obstruction
- Pyelonephritis › chronic › obstructive
- Pyelonephritis › chronic › associated with ureteral obstruction or stricture
- Obstruction, obstructed, obstructive › ureter (functional) (pelvic junction) NEC › with › pyelonephritis (chronic)
- Kink, kinking › ureter (pelvic junction) › with › pyelonephritis (chronic)
- Nephritis, nephritic (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic) › tubulo-interstitial (in) › chronic (infectious) › obstructive
Inclusion Terms
- Pyelonephritis (chronic) associated with anomaly of pelviureteric junction
- Pyelonephritis (chronic) associated with anomaly of pyeloureteric junction
- Pyelonephritis (chronic) associated with crossing of vessel
- Pyelonephritis (chronic) associated with kinking of ureter
- Pyelonephritis (chronic) associated with obstruction of ureter
- Pyelonephritis (chronic) associated with stricture of pelviureteric junction
- Pyelonephritis (chronic) associated with stricture of ureter
U.S. Hospital Utilization
- An estimated 3,345 U.S. inpatient stays in 2023 included N11.1 among the documented diagnoses.
- 525 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 onlyIf 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