Acute kidney injury is classified under ICD-10-CM code N17, which requires specifying the associated pathology. Common billable codes include N17.0 (tubular necrosis), N17.1 (acute cortical necrosis), N17.2 (medullary necrosis), and N17.9 (unspecified).
Primary codes
Billable
Billable
Extension
—
7th character
—
POA exempt
No
Inclusion terms
- Acute kidney injury (nontraumatic)
Type 2 excludes
- traumatic kidney injury (S37.0-)
Coding risks
- Assigning when documentation supports a more specific code
Hierarchy
Code comparison
Compare key differences between related codes to select the most specific option.
| Code | Description | Scenario |
|---|---|---|
| N17.9 | Acute kidney failure, unspecified | AKI documented without specification of tubular, cortical, or medullary necrosis in the record. |
| N17.0 | Acute kidney failure with tubular necrosis | AKI with tubular necrosis (ATN) documented, cortical and medullary necrosis absent. |
| N17.1 | Acute kidney failure with acute cortical necrosis | AKI with acute cortical necrosis documented, distinguishing it from tubular or medullary necrosis findings. |
| N17.2 | Acute kidney failure with medullary necrosis | AKI with medullary necrosis specifically documented, distinguishing it from tubular or cortical necrosis findings. |
Select the most specific code supported by the encounter documentation. More specific codes improve reimbursement accuracy and reduce audit risk.
Code ranges
Acute kidney failure
Category covering acute kidney injury with various pathological findings including tubular necrosis, cortical necrosis, and medullary necrosis.
Acute kidney failure and chronic kidney disease
Sub-chapter grouping acute kidney failure, chronic kidney disease, and unspecified kidney failure conditions.
Chronic kidney disease
Progressive, long-standing loss of kidney function classified by stage severity from mild to end-stage renal disease.
Unspecified kidney failure
Kidney failure not documented as acute or chronic, used only when no further specification is available.
Abnormal results of kidney function studies
Abnormal renal function test findings without an established diagnosis of kidney failure or injury.
Coding risks
Avoid these common coding issues when reporting Acute Kidney Injury.
Impact
Assigning N17.9 without explicit lesion documentation may miscode when tubular or cortical necrosis is actually present.
Mitigation
Consider querying the provider when lesion type is absent rather than inferring from creatinine trends or urine studies.
Related codes
Ancillary and co-coding
Codes commonly reported with the primary diagnosis on the same claim.
Z-code variants
Family history, personal history, or screening encounter codes related to this condition.
In pregnancy
Pregnancy-specific O-code adaptations used in place of the primary when the condition occurs during or complicates pregnancy.
Differential codes
Alternative or commonly confused codes to consider when documentation suggests a different condition than the primary diagnosis.
Frequently asked questions
Use N17.9 only when the record documents AKI without specifying tubular, cortical, or medullary necrosis. More specific N17 subcodes take precedence when documented.
References
Compiled from the following authoritative coding references. Last updated 2026-08-04.