Acute Kidney Injury ICD-10-CM codes

Acute kidney injury and acute kidney failure (or acute renal failure) all index to category N17. N17.9 (acute kidney failure, unspecified) is the code for AKI without a documented mechanism and is the most frequently reported. N17.0 (acute tubular necrosis), N17.1 (acute cortical necrosis) and N17.2 (medullary necrosis) require the provider to document that specific lesion; a lab-based AKI stage does not support N17.0. N17.8 is other acute kidney failure.

Acute renal insufficiency is not the same as AKI in ICD-10-CM: it indexes to N28.9 (disorder of kidney, unspecified), so the term should prompt a query if AKI is clinically meant. Kidney failure with no acuity stated is N19. AKI on top of CKD is reported with both N17.- and the N18 stage code (for example N17.9 with N18.30). If a patient with CKD is in AKI, do not assign a higher CKD stage based on the acute creatinine.

Sequencing follows the reason for admission. When dehydration causes AKI and both are treated, the AKI is generally sequenced first as the more serious condition treated, with E86.0 as a secondary code; when AKI is a complication of a procedure, N99.0 is the code, not N17. Oliguria or anuria without a kidney diagnosis is R34, and abnormal creatinine alone is R94.4. Do not assign N17 for AKI documented only as ruled out.