ICD-10-CM 2027 diagnosis code

N27Small kidney of unknown cause

Not billable — use a more specific code

N27 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About N27

N27 is the ICD-10-CM diagnosis code for small kidney of unknown cause. It belongs to block N25-N29 (other disorders of kidney and ureter) and chapter 14 (diseases of the genitourinary system). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: N27.0 (unilateral), N27.1 (bilateral) and N27.9 (unspecified).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under N27

Coding notes

IncludesFurther defines the content of the category

oligonephronia

Notes that apply from higher levels

Instructions written at a parent level also apply to N27.

Broader instructions also apply from N25-N29 Other disorders of kidney and ureter and Chapter 14: Diseases of the genitourinary system.

Codes whose notes reference N27

N26Excludes1

Code history

2016
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2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about N27

Is N27 billable?: No. N27 is a header code. Report one of its more specific subcodes instead.