2027 ICD-10-CM Diagnosis Code N27.9Small kidney, unspecified

ICD-10-CM Codes›N00–N99›N25-N29›N27

ICD-10-CM N27.9
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

N27.9 is a billable ICD-10-CM diagnosis code for small kidney, unspecified. 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 contracted 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
N27.9
Billable Status
Yes — Valid for Submission
Code Describes
Small kidney, unspecified
Short Description
Small kidney, unspecified
Same as the full description in the CMS dataset.
Parent Code
N27
Small kidney of unknown cause

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN25-N29Other disorders of kidney and ureter
CategoryN27Small kidney of unknown cause
This CodeN27.9Small kidney, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Contracted kidney
  • Irregularly contracted kidney
  • Small kidney
  • Small kidney of unknown cause

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N27.9: its own notes plus those printed at N27, block N25-N29, 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.

From N27 Small kidney of unknown cause applies to 3 codes
  • oligonephronia

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 N27.9, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming N27.9: they are not reported together with it, unless the two conditions are unrelated.

  • N26 Unspecified contracted kidney
    small kidney of unknown cause (N27.-) names N27.-, 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 N27.9 to ICD-9-CMHistory

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

ICD-9-CM
589.9 Small kidney NOS
Exact Match The mapping is direct, with no qualifiers.

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 N27.9Overview

What is the ICD-10 code for small kidney, unspecified?

The ICD-10-CM code for small kidney, unspecified is N27.9 (sometimes written as N279). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is N27.9 (Small kidney of unknown cause) a billable code?

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

What MS-DRG does N27.9 group to?

When small kidney, unspecified 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.

What is the ICD-9 equivalent of N27.9?

Under the General Equivalence Mappings, small kidney, unspecified converts to ICD-9-CM 589.9 (small kidney NOS). The mapping is a direct match.