ICD-10-CM > N00-N99 > N10-N16 > N11 N11 Chronic tubulo-interstitial nephritis Non-Billable/Non-Specific Includes chronic infectious interstitial nephritischronic pyelitischronic pyelonephritis Use Additional code (B95-B97), to identify infectious agent. Codes N11.0Nonobstructive reflux-associated chronic pyelonephritisN11.1Chronic obstructive pyelonephritisN11.8Other chronic tubulo-interstitial nephritisN11.9Chronic tubulo-interstitial nephritis, unspecified