Obstructive and reflux uropathy (N13) ICD-10-CM
The N13 code range covers obstructive and reflux uropathy with 23 ICD-10-CM diagnosis codes. 18 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Codes in the N13 Range 23 codes · 18 billable
- N13 Obstructive and reflux uropathyNon-billable
- N13.0 Hydronephrosis with ureteropelvic junction obstruction
- N13.1 Hydronephrosis with ureteral stricture, not elsewhere classified
- N13.2 Hydronephrosis with renal and ureteral calculous obstruction
- N13.3 Other and unspecified hydronephrosisNon-billable
- N13.30 Unspecified hydronephrosis
- N13.39 Other hydronephrosis
- N13.4 Hydroureter
- N13.5 Crossing vessel and stricture of ureter without hydronephrosis
- N13.6 Pyonephrosis
- N13.7 Vesicoureteral-refluxNon-billable
- N13.70 Vesicoureteral-reflux, unspecified
- N13.71 Vesicoureteral-reflux without reflux nephropathy
- N13.72 Vesicoureteral-reflux with reflux nephropathy without hydroureterNon-billable
- N13.721 Vesicoureteral-reflux with reflux nephropathy without hydroureter, unilateral
- N13.722 Vesicoureteral-reflux with reflux nephropathy without hydroureter, bilateral
- N13.729 Vesicoureteral-reflux with reflux nephropathy without hydroureter, unspecified
- N13.73 Vesicoureteral-reflux with reflux nephropathy with hydroureterNon-billable
- N13.731 Vesicoureteral-reflux with reflux nephropathy with hydroureter, unilateral
- N13.732 Vesicoureteral-reflux with reflux nephropathy with hydroureter, bilateral
- N13.739 Vesicoureteral-reflux with reflux nephropathy with hydroureter, unspecified
- N13.8 Other obstructive and reflux uropathy
- N13.9 Obstructive and reflux uropathy, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the N13 range.
Azotemia
A biochemical abnormality referring to an elevation of BLOOD UREA NITROGEN and CREATININE. Azotemia can be produced by KIDNEY DISEASES or other extrarenal disorders. When azotemia becomes associated with a constellation of clinical signs, it is termed UREMIA.
Hydronephrosis
Abnormal enlargement or swelling of a KIDNEY due to dilation of the KIDNEY CALICES and the KIDNEY PELVIS. It is often associated with obstruction of the URETER or chronic kidney diseases that prevents normal drainage of urine into the URINARY BLADDER.
Pyonephrosis
Distention of KIDNEY with the presence of PUS and suppurative destruction of the renal parenchyma. It is often associated with renal obstruction and can lead to total or nearly total loss of renal function.
Retroperitoneal Fibrosis
A slowly progressive condition of unknown etiology, characterized by deposition of fibrous tissue in the retroperitoneal space compressing the ureters, great vessels, bile duct, and other structures. When associated with abdominal aortic aneurysm, it may be called chronic periaortitis or inflammatory perianeurysmal fibrosis.
About the N13 Code Range
ICD-10 code section N13 covers obstructive and reflux uropathy, conditions characterized by blockage or backward flow of urine affecting the kidneys and ureters. These codes are used to specify various forms of urinary tract obstruction and reflux that can impair kidney function.
This section includes detailed codes for different types of hydronephrosis caused by specific obstructions, such as ureteropelvic junction blockage (N13.0), ureteral strictures (N13.1), and kidney or ureter stones causing obstruction (N13.2). It also addresses hydroureter, which is a dilation of the ureter due to obstruction (N13.4), and pyonephrosis, an infected hydronephrosis (N13.6). Vesicoureteral reflux (backflow of urine from bladder to kidney) with or without reflux nephropathy is classified under N13.7 and its subcodes, clarifying the presence and side of kidney damage. For example, primary or secondary vesicoureteral reflux is captured by codes like N13.70 and N13.71. Other obstructive uropathies related to prostate enlargement, malignancy, or mechanical causes fall under N13.8. When the obstruction or reflux is unspecified, N13.9 is used. These codes help healthcare providers document and identify specific urinary tract obstructions or reflux conditions precisely, assisting in diagnosis, treatment planning, and reporting.
Questions About This Page
How many billable codes are in the N13 range?
Of the 23 codes in this range, 18 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the N13 range classify?
The range classifies obstructive and reflux uropathy. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
