N11.9 — Chronic tubulo-interstitial nephritis, unspecified
Is N11.9 billable?
Yes, but N11.9 is an unspecified code. N11.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, N11.9 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting N11.9 — the more specific alternatives are listed below.
N11.9 at a glance
| Code | N11.9 |
|---|---|
| Description | Chronic tubulo-interstitial nephritis, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does N11.9 group to?
N11.9 sits in MDC 11 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 689Kidney and Urinary Tract Infections with MCCmedical
- 690Kidney and Urinary Tract Infections without MCCmedical
As a secondary diagnosis, N11.9 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG. It also carries Hospital-Acquired Condition category 06.
How is N11.9 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to N11.9. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Pyelitis › chronic (congenital) (uremic)
- Pyelonephritis › chronic
- Pyelonephrosis › chronic (obstructive)
- Nephritis, nephritic › tubulo-interstitial › chronic (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
- Pyelitis › with › contracted kidney (congenital) (uremic)
- Pyelonephritis › with › contracted kidney
Inclusion terms
Alternative wording in documentation that is classified to N11.9.
- Chronic interstitial nephritis NOS
- Chronic pyelitis NOS
- Chronic pyelonephritis NOS
Excludes1 — never code together — inherited from N10-N16
The conditions below can never be reported together with N11.9 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- pyeloureteritis cystica (N28.85)
Use additional code — inherited from N11
Report an additional code alongside N11.9 to fully describe the condition. N11.9 is sequenced first.
- code (B95-B97), to identify infectious agent.
Excludes2 — not included here — inherited from Chapter 14
The conditions below are not part of N11.9, but a patient may have both at the same time. When documentation supports it, N11.9 and the excluded code may both be reported.
- 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)
How long has N11.9 existed?
N11.9 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.