2026 ICD-10-CM Diagnosis Code N16Renal tubulo-interstitial disorders in diseases classified elsewhere
ICD-10-CM Codes›N00–N99›N10-N16›N16
- Billable — Valid for Submission
- Not Chronic
N16 is a billable ICD-10-CM diagnosis code for renal tubulo-interstitial disorders in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 698 through 700. The code is a manifestation code that cannot be reported as the principal diagnosis. Coders also document this condition as acute nephritis due to another disorder. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nephritis; nephrosis; renal sclerosis.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for N16.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute nephritis due to another disorder
- Acute tubulointerstitial nephritis
- Acute tubulo-interstitial nephritis due to immunological disorder
- Immunoglobulin G4 related disease
- Immunoglobulin G4 related kidney disease
- Pyelitis
- Pyelitis associated with another disorder
- Pyelonephritis associated with another disorder
- Renal tubulo-interstitial disorder due to cystinosis
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Pyelonephritis
- Tubulo-interstitial nephritis
Code First
- underlying disease, such as:
- brucellosis A23.0 A23.9
- cryoglobulinemia D89.1
- glycogen storage disease E74.0
- leukemia C91 C95
- lymphoma C81.0 C85.9 C96.0 C96.9
- multiple myeloma C90.0
- sepsis A40.0 A41.9
- Wilson's disease E83.01
Type 1 Excludes
- diphtheritic pyelonephritis and tubulo-interstitial nephritis A36.84
- pyelonephritis and tubulo-interstitial nephritis in candidiasis B37.49
- pyelonephritis and tubulo-interstitial nephritis in cystinosis E72.04
- pyelonephritis and tubulo-interstitial nephritis in salmonella infection A02.25
- pyelonephritis and tubulo-interstitial nephritis in sarcoidosis D86.84
- pyelonephritis and tubulo-interstitial nephritis in Sjogren syndrome M35.04
- pyelonephritis and tubulo-interstitial nephritis in systemic lupus erythematosus M32.15
- pyelonephritis and tubulo-interstitial nephritis in toxoplasmosis B58.83
- renal tubular degeneration in diabetes E08 E13
- syphilitic pyelonephritis and tubulo-interstitial nephritis A52.75
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
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.Pyelitis
inflammation of the renal pelvis.
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 N16 to ICD-9-CMHistory
Code HistoryHistory
Questions About N16Overview
Is N16 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report renal tubulo-interstitial disorders in diseases classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does N16 group to?
On inpatient claims, renal tubulo-interstitial disorders in diseases classified elsewhere maps to MS-DRG 698, 699, 700, with relative weights from 0.6899 to 1.6544 depending on complications. Higher weights mean higher Medicare reimbursement.
Can N16 be a principal diagnosis?
No. This is a manifestation code: renal tubulo-interstitial disorders in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What is the ICD-9 equivalent of N16?
Under the General Equivalence Mappings, renal tubulo-interstitial disorders in diseases classified elsewhere converts to ICD-9-CM 583.81 (nephritis NOS in oth dis) and 590.81 (pyelonephrit in oth dis). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
