N20.0 Calculus of kidney
The ICD-10-CM code for Calculus of kidney is N20.0 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- N20-N23: Urolithiasis (N20-N23)
- Category N20
- 5 codes (4 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to N20.0:
- Calculus, calculi, calculous › kidney (impacted) (multiple) (pelvis) (recurrent) (staghorn)
- Stone (s) › renal
- Stone (s) › kidney
- Calculus, calculi, calculous › pyelitis (impacted) (recurrent)
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › kidney › with calculus
- Calculus, calculi, calculous › diverticulum › kidney
- Infection, infected, infective (opportunistic) › kidney (cortex) (hematogenous) › with calculus
Inclusion Terms
- Nephrolithiasis NOS
- Renal calculus
- Renal stone
- Staghorn calculus
- Stone in kidney
U.S. Hospital Utilization
- An estimated 229,425 U.S. inpatient stays in 2023 included N20.0 among the documented diagnoses.
- 10,720 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