N13.4 ICD-10-CM Code: Hydroureter
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Renal tubulo-interstitial diseases (N10-N16)
N13.4
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceHydroureter
Swelling of the ureter (the tube carrying urine from kidney to bladder) due to urine backup, typically from an obstruction below the ureter.
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
OfficialICD-10-CM does not list inclusion terms for N13.4 in this effective period.
Excludes 2
Official- calculus of kidney and ureter without hydronephrosis (N20.-)
- congenital obstructive defects of renal pelvis and ureter (Q62.0-Q62.3)
- hydronephrosis with ureteropelvic junction obstruction (Q62.11)
- obstructive pyelonephritis (N11.1)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for N13.4 in this effective period.
Excludes 1
Official- congenital hydroureter (Q62.3-)
- hydroureter with infection (N13.6)
- vesicoureteral-reflux with hydroureter (N13.73-)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for N13.4 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for N13.4 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for N13.4 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 N13.4 an HCC code?
No. N13.4 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- N13.4
- Description
- Hydroureter
- 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
N13.4 is the ICD-10-CM diagnosis code for hydroureter. Swelling of the ureter (the tube carrying urine from kidney to bladder) due to urine backup, typically from an obstruction below the ureter. N13.4 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering renal tubulo-interstitial diseases (n10-n16).
N13.4 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.
Distinguish between hydroureter alone and hydroureter with hydronephrosis, which would require additional coding.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N13.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Distinguish between hydroureter alone and hydroureter with hydronephrosis, which would require additional coding
- •Document whether the condition is unilateral or bilateral