ICD-10-CM 2027
ICD-10 code for kidney small
From the official ICD-10-CM alphabetic index entry “Small (ness) › kidney (unknown cause)”. Page updated September 29, 2026.
About coding kidney small
The ICD-10-CM code for kidney small is N27.9 (Small kidney, unspecified). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on N27.9.
Within N27, choose N27.9 (unspecified) only when documentation doesn't support a more specific option: unilateral (N27.0) and bilateral (N27.1).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 698 (Other Kidney and Urinary Tract Diagnoses with MCC, relative weight 1.6398), DRG 699 (Other Kidney and Urinary Tract Diagnoses with CC, relative weight 1.0003) and DRG 700 (Other Kidney and Urinary Tract Diagnoses without CC/MCC, relative weight 0.6741), in MDC 11 (Diseases and Disorders of the Kidney and Urinary Tract), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific kidney small codes (official index)
Common questions about kidney small ICD-10 codes
What is the ICD-10 code for kidney small?
- N27.9 — Small kidney, unspecified. More specific codes apply when the documentation supports them: N27.1, N27.0.
What is the ICD-10 code for bilateral kidney small?
- N27.1 — Small kidney, bilateral.
What is the ICD-10 code for unilateral kidney small?
- N27.0 — Small kidney, unilateral.
Is N27.9 billable?
- Yes. N27.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N27.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N27.9 as a principal diagnosis.
Is N27.9 a CC or MCC?
- No. N27.9 is neither a CC nor an MCC under MS-DRG v44.0.