2027 ICD-10-CM Diagnosis Code N11.9Chronic tubulo-interstitial nephritis, unspecified
ICD-10-CM Codes›N00–N99›N10-N16›N11
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
N11.9 is a billable ICD-10-CM diagnosis code for chronic tubulo-interstitial nephritis, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 689 through 690, 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 228 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Urinary tract infections.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute on chronic tubulointerstitial nephritis
- Chronic pyelitis
- Chronic pyelonephritis
- Chronic pyelonephritis with medullary necrosis
- Chronic tubulointerstitial nephritis
- Chronic tubulo-interstitial nephritis due to connective tissue disorder
- Chronic tubulointerstitial nephritis due to ischemia
- Chronic tubulointerstitial nephritis due to metabolic disease
- Chronic tubulointerstitial nephritis due to neoplastic disease
- Chronic tubulointerstitial nephritis following renal transplantation
- Chronic urinary tract infection
- Idiopathic chronic tubulointerstitial nephritis
- Ischemic nephropathy
- Pyelitis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to N11.9: its own notes plus those printed at N11, block N10-N16, and Chapter 14. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- chronic infectious interstitial nephritis
- chronic pyelitis
- chronic pyelonephritis
- pyelonephritis
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Chronic interstitial nephritis NOS
- Chronic pyelitis NOS
- Chronic pyelonephritis NOS
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- pyeloureteritis cystica (N28.85)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may 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)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name N11.9, its category, or a range that includes it.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Nephritis, nephritic (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic) N05.9
Pyelitis (congenital) (uremic) See Also: Pyelonephritis;
contracted kidney N11.9
chronic N11.9
Pyelonephritis See Also: Nephritis, tubulo-interstitial;
contracted kidney N11.9
chronic N11.9
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Kidney Diseases
You have two kidneys, each about the size of your fist. They are near the middle of your back, just below the rib cage. Inside each kidney there are about a million tiny structures called nephrons. They filter your blood. They remove wastes and extra water, which become urine. The urine flows through tubes called ureters.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert N11.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About N11.9Overview
What is the ICD-10 code for chronic tubulo-interstitial nephritis, unspecified?
The ICD-10-CM code for chronic tubulo-interstitial nephritis, unspecified is N11.9 (sometimes written as N119). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is N11.9 (Chronic tubulo-interstitial nephritis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chronic tubulo-interstitial nephritis, unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does N11.9 group to?
When chronic tubulo-interstitial nephritis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 689, 690, with relative weights from 0.8008 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is N11.9 a CC or MCC?
CMS lists N11.9 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 228 closely related codes in its exclusion list.
Can N11.9 be reported with N28.85?
Not as a rule. The Excludes1 note at block N10-N16, which applies to N11.9, lists "pyeloureteritis cystica (N28.85)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
