2027 ICD-10-CM Diagnosis Code N26.1Atrophy of kidney (terminal)

ICD-10-CM Codes›N00–N99›N25-N29›N26

ICD-10-CM N26.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

N26.1 is a billable ICD-10-CM diagnosis code for atrophy of kidney (terminal). It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 698 through 700. Coders also document this condition as atrophy of cortex of kidney. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified diseases of kidney and ureters.

Code Identity

ICD-10-CM Code
N26.1
Billable Status
Yes — Valid for Submission
Code Describes
Atrophy of kidney (terminal)
Short Description
Atrophy of kidney (terminal)
Same as the full description in the CMS dataset.
Parent Code
N26
Unspecified contracted kidney

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN25-N29Other disorders of kidney and ureter
CategoryN26Unspecified contracted kidney
This CodeN26.1Atrophy of kidney (terminal)

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Atrophy of cortex of kidney
  • Atrophy of kidney
  • Atrophy of left kidney
  • Atrophy of renal tubule
  • Atrophy of right kidney
  • Bilateral atrophy of kidney

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N26.1: its own notes plus those printed at N26, block N25-N29, and Chapter 14. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From N26 Unspecified contracted kidney applies to 3 codes
  • contracted kidney due to hypertension (I12.-)
  • diffuse sclerosing glomerulonephritis (N05.8.-)
  • hypertensive nephrosclerosis (arteriolar) (arteriosclerotic) (I12.-)
  • small kidney of unknown cause (N27.-)

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.

From Block N25-N29 Other disorders of kidney and ureter applies to 22 codes
  • disorders of kidney and ureter with urolithiasis (N20-N23)
From Chapter 14 (N00-N99) Diseases of the genitourinary system applies to 838 codes
  • 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)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name N26.1, its category, or a range that includes it.

Includes 1

These notes mention N26.1.

  • I12 Hypertensive chronic kidney disease
    any condition in N18 and N26 - due to hypertension names N26, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN006
Other specified and unspecified diseases of kidney and ureters
Default principal diagnosis: inpatient Yes · outpatient Yes

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 N26.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
587 Renal sclerosis NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About N26.1Overview

What is the ICD-10 code for atrophy of kidney (terminal)?

The ICD-10-CM code for atrophy of kidney (terminal) is N26.1 (sometimes written as N261). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is N26.1 (Unspecified contracted kidney) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report atrophy of kidney (terminal) on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does N26.1 group to?

When atrophy of kidney (terminal) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 699, 698, 700, with relative weights from 0.6740 to 1.6400 depending on complications. Higher weights mean higher Medicare reimbursement.

Can N26.1 be reported with a code from I12?

Not as a rule. The Excludes1 note at N26, which applies to N26.1, lists "contracted kidney due to hypertension (I12.-)". 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).

What is the ICD-9 equivalent of N26.1?

Under the General Equivalence Mappings, atrophy of kidney (terminal) converts to ICD-9-CM 587 (renal sclerosis NOS). The mapping is approximate, so confirm the match fits the documentation.