N20.1 ICD-10-CM Code: Calculus of ureter
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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Urolithiasis (N20-N23)
N20.1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCalculus of ureter
A ureteral stone is a kidney stone that has moved into the ureter (the tube carrying urine from kidney to bladder) and may cause severe pain and blockage.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Calculus of the ureteropelvic junction
- Ureteric stone
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for N20.1 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for N20.1 in this effective period.
Excludes 1
Official- nephrocalcinosis (E83.59)
- that with hydronephrosis (N13.2)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for N20.1 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for N20.1 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for N20.1 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is N20.1 an HCC code?
No. N20.1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- N20.1
- Description
- Calculus of ureter
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
N20.1 is the ICD-10-CM diagnosis code for calculus of ureter. A ureteral stone is a kidney stone that has moved into the ureter (the tube carrying urine from kidney to bladder) and may cause severe pain and blockage. N20.1 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering urolithiasis (n20-n23).
N20.1 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Specify laterality (right or left ureter) in documentation.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N20.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Specify laterality (right or left ureter) in documentation
- •Document whether the stone is causing hydronephrosis or obstruction