N11.9
Chronic tubulo-interstitial nephritis, unspecified
N11.9 (also written N119) is a billable ICD-10-CM diagnosis code for chronic tubulo-interstitial nephritis, unspecified. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 4 codes in category N11 (Chronic tubulo-interstitial nephritis). The Alphabetic Index lists it under 6 entries. Its coding notes include a Use additional code instruction, 1 Excludes1 entry and 8 Excludes2 entries.
Use additional code
Add the listed code as a secondary code, if known.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (8 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Gastrointestinal tract and Genitourinary system clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 228 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CHAC
On the CMS list of hospital-acquired conditions (HAC 06: Catheter-Associated Urinary Tract Infection (UTI)). When the claim reports it with a present-on-admission (POA) indicator of N (not present) or U (documentation insufficient), CMS does not pay the CC or MCC DRG for it. A POA of Y (present) or W (clinically undetermined) is paid normally.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix I; CMS Hospital-Acquired Conditions (HAC) Coding page, POA indicator payment tableIncludes
Further defines or gives examples of the content of the category.
- chronic infectious interstitial nephritis
- chronic pyelitis
- chronic pyelonephritis
Also from chapter/block level (1 note)
- pyelonephritis
Inclusion terms
Conditions classified to this code.
- Chronic interstitial nephritis NOS
- Chronic pyelitis NOS
- Chronic pyelonephritis NOS
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 6 entries
- Nephritis, nephritic (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic), tubulo-interstitial (in), chronic (infectious)
- Pyelitis (congenital) (uremic), chronic
- Pyelitis (congenital) (uremic), with, contracted kidney
- Pyelonephritis, chronic
- Pyelonephritis, with, contracted kidney
- Pyelonephrosis (obstructive), chronic