Chronic tubulo-interstitial nephritis (N11) ICD-10-CM
The N11 code range covers chronic tubulo-interstitial nephritis with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- chronic infectious interstitial nephritis
- chronic pyelitis
- chronic pyelonephritis
Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Codes in the N11 Range 5 codes · 4 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the N11 range.
Pyelitis
Inflammation of the KIDNEY PELVIS and KIDNEY CALICES where urine is collected before discharge, but does not involve the renal parenchyma (the NEPHRONS) where urine is processed.
About the N11 Code Range
The ICD-10 codes under section N11 are specifically used to classify various forms of chronic tubulo-interstitial nephritis, a long-term inflammation affecting the kidney’s tubules and surrounding interstitial tissue. These codes include different types of chronic pyelonephritis, both reflux-associated and obstructive, as well as other chronic interstitial kidney inflammations.
This group covers conditions like nonobstructive reflux-associated chronic pyelonephritis (N11.0), often referred to by synonyms such as “chronic urinary tract infection” and “familial non-obstructive reflux-associated chronic pyelonephritis.” It also includes chronic obstructive pyelonephritis (N11.1), known alternatively as “obstructive pyelonephritis.” For other less common types, N11.8 encompasses chronic infections and interstitial nephritis variants, including “xanthogranulomatous pyelonephritis” and “renal interstitial fibrosis.” Finally, N11.9 captures unspecified or idiopathic chronic tubulo-interstitial nephritis, linking it to causes like metabolic, neoplastic, ischemic diseases, or complications from renal transplantation. Using these codes helps medical coders accurately document specific chronic kidney inflammations for diagnosis and treatment tracking.
Questions About This Page
How many billable codes are in the N11 range?
Of the 5 codes in this range, 4 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 N11 range classify?
The range classifies chronic tubulo-interstitial nephritis. 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.
