The term kidney stone ICD 10 refers to the standardized diagnostic codes used in the United States to document kidney stones and related conditions under the ICD-10-CM classification system. These codes are mandatory for clinical documentation, insurance claims, epidemiological tracking, and healthcare analytics.
Kidney stones, medically termed nephrolithiasis or urolithiasis, are solid mineral deposits formed in the kidneys or urinary tract. Accurate ICD-10 coding ensures correct diagnosis reporting, appropriate reimbursement, and continuity of patient care.
What Is ICD-10-CM?
ICD-10-CM (International Classification of Diseases, Tenth Revision, Clinical Modification) is maintained by the Centers for Medicare & Medicaid Services (CMS) and the National Center for Health Statistics (NCHS).
Its purposes include:
- Standardizing disease classification
- Supporting medical billing and reimbursement
- Enabling population health analysis
- Improving clinical documentation precision
Kidney stone diagnoses fall primarily under Chapter 14: Diseases of the Genitourinary System (N00–N99).
Primary Kidney Stone ICD 10 Codes
ICD-10 Code N20 Series (Calculus of Kidney and Ureter)
N20.0 – Calculus of kidney
- Used when stones are located within the kidney
- Most commonly reported kidney stone ICD 10 code
- Applies regardless of stone composition unless specified elsewhere
N20.1 – Calculus of ureter
- Used for stones that have migrated from the kidney into the ureter
- Often associated with acute renal colic
N20.2 – Calculus of kidney with calculus of ureter
- Used when stones are present in both kidney and ureter at the same encounter
N20.9 – Calculus of urinary tract, unspecified
- Used only when documentation does not specify stone location
- Should be avoided when clinical details are available
Related and Secondary ICD-10 Codes
Additional Codes Commonly Used With Kidney Stones
N21.0 – Calculus in bladder
- Not a kidney stone but part of the urinary stone spectrum
N23 – Unspecified renal colic
- Used for severe flank pain suggestive of stones when imaging confirmation is pending
R31.0 / R31.9 – Hematuria
- Frequently coded alongside kidney stone ICD 10 when blood in urine is present
N39.0 – Urinary tract infection
- Used when infection occurs secondary to obstructing stones
ICD-10 Coding Based on Stone Location
| Stone Location | ICD-10 Code |
|---|---|
| Kidney only | N20.0 |
| Ureter only | N20.1 |
| Kidney + ureter | N20.2 |
| Urinary tract unspecified | N20.9 |
| Bladder | N21.0 |
Accurate anatomical documentation directly impacts correct ICD-10 assignment.
Clinical Documentation Requirements
For correct kidney stone ICD 10 coding, medical records should clearly state:
- Stone location (kidney, ureter, bladder)
- Laterality if applicable
- Associated complications (infection, obstruction)
- Imaging confirmation (CT, ultrasound)
- Symptoms such as hematuria or renal colic
Incomplete documentation leads to downcoding, claim denials, or audit risk.
Kidney Stone Types and ICD-10 Limitations
ICD-10-CM does not differentiate kidney stones by chemical composition.
Common stone types:
- Calcium oxalate
- Calcium phosphate
- Uric acid
- Struvite
- Cystine
Stone composition is clinically relevant but does not change the kidney stone ICD 10 code. Composition is documented separately in clinical notes, not diagnosis codes.
Diagnostic Confirmation and Coding Timing
Kidney stone ICD-10 codes are typically assigned when:
- Imaging confirms stones (CT KUB, ultrasound)
- Stones are visualized during procedures
- Clinical diagnosis is definitive
Suspected stones without confirmation may initially use symptom codes such as flank pain or renal colic.
Procedural vs Diagnostic Coding
ICD-10 codes describe diagnosis, not treatment.
Common procedures include:
- Extracorporeal shock wave lithotripsy (ESWL)
- Ureteroscopy
- Percutaneous nephrolithotomy
These require CPT or ICD-10-PCS codes, not kidney stone ICD 10 diagnosis codes.
Pediatric and Recurrent Kidney Stones
The same ICD-10 codes apply regardless of patient age.
For recurrent stones:
- The same N20 codes are reused
- Frequency and recurrence are documented in clinical notes, not ICD-10
There is no separate ICD-10 code for recurrent nephrolithiasis.
Unique Clinical Takeaways
1. Obstruction Severity Is Not Reflected in ICD-10 Codes
ICD-10 kidney stone codes do not capture the degree of urinary obstruction. A small distal ureteral stone causing hydronephrosis uses the same code as a non-obstructive renal stone. Clinicians must document obstruction separately to justify imaging, hospitalization, or intervention.
2. Infection With Stones Requires Dual Coding
When kidney stones coexist with infection, both conditions must be coded. ICD-10 does not combine nephrolithiasis and infection into a single code. Failure to add infection codes can underrepresent clinical severity and affect reimbursement.
3. Pain Location Does Not Equal Stone Location
Flank pain does not guarantee kidney involvement. Distal ureteral stones often present with groin pain but still require N20.1 coding. Coding must follow imaging-confirmed anatomy, not symptom location.
Common Coding Errors to Avoid
- Using N20.9 when stone location is documented
- Coding symptoms instead of confirmed diagnosis
- Omitting secondary complication codes
- Confusing bladder stones with kidney stones
- Assigning procedure codes as diagnosis codes
Importance of Accurate Kidney Stone ICD 10 Coding
Correct coding supports:
- Proper insurance reimbursement
- Reduced claim denials
- Accurate public health data
- Improved care coordination
- Legal and compliance protection
Inaccurate coding increases audit risk and disrupts clinical data integrity.
ICD-10 Coding and U.S. Insurance Claims
All U.S. payers, including:
- Medicare
- Medicaid
- Commercial insurers
Require ICD-10 diagnosis codes. Kidney stone ICD 10 codes must align with imaging and physician documentation to pass medical necessity reviews.
Prognosis and Follow-Up Documentation
ICD-10 does not include prognosis indicators. Follow-up care should document:
- Stone passage
- Resolution on imaging
- Recurrence risk factors
- Preventive counseling
Diagnosis codes remain unchanged unless stone location or condition changes.
Medical Disclaimer
This content is for informational and educational purposes only and does not substitute professional medical advice, diagnosis, or treatment. Always consult a licensed healthcare provider for clinical decisions and coding validation.