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ICD-10 Guide
DiagnosesAcute On Chronic Renal Failure

Acute On Chronic Renal Failure

ICD-10 Coding for Acute on Chronic Renal Failure(N17.9, N18.3)

PRIMARY SPECIALTYNephrology
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Acute On Chronic Renal Failure?
Essential facts and insights about Acute on Chronic Renal Failure

Key Clinical Considerations:

  • Patients may present with symptoms such as fatigue, edema, hypertension, and decreased urine output.
  • Laboratory findings typically include elevated serum creatinine and blood urea nitrogen (BUN) levels, along with electrolyte imbalances.
  • Physical examination may reveal signs of fluid overload, such as peripheral edema or pulmonary congestion.
  • Imaging studies like ultrasound may show kidney size changes or obstruction, while CT scans can help identify underlying causes.
  • Severity is often assessed using the KDIGO classification for acute kidney injury (AKI) in the context of chronic kidney disease (CKD).

Clinical Information

Clinical Criteria & Documentation Requirements

  • Medical records must clearly document the acute exacerbation of chronic renal failure, including onset and duration of symptoms.
  • Specific terminology such as 'acute on chronic renal failure' must be used to ensure clarity in diagnosis.
  • Examples include documenting the patient's baseline renal function and any recent changes in laboratory values.
  • Medical necessity must be established through documentation of the patient's clinical status and the need for treatment.
  • Quality measures may require documentation of patient education regarding renal disease management and follow-up care.

Coding Guidelines

Usage Guidelines & Examples

  • Use this diagnosis code when a patient with chronic renal failure presents with acute kidney injury symptoms.
  • Do not use this code if the patient has only acute renal failure without a history of chronic kidney disease.
  • Similar codes include N17.0 (Acute kidney failure, unspecified) and N18.9 (Chronic kidney disease, unspecified), which should not be used interchangeably.
  • Common errors include misclassifying acute renal failure as acute on chronic without proper documentation of chronicity.
  • In complex cases, ensure to document the stage of chronic kidney disease to support the acute on chronic diagnosis.

Code Exclusions

Important Exclusions

  • Conditions explicitly excluded include acute renal failure without chronic disease history, such as acute tubular necrosis.
  • Alternative codes for excluded conditions may include N17.0 for acute kidney failure without chronicity.
  • Exclusions are based on the absence of chronic kidney disease history, which is critical for accurate coding.
  • Common mistakes include coding acute renal failure as acute on chronic without confirming the chronicity.
  • Related but distinct conditions include chronic renal failure without acute exacerbation, which should be coded differently.

Related ICD-10 Codes

Primary Codes
N17.9
Acute kidney failure, unspecified
N18.3
Chronic kidney disease, stage 3
Ancillary Codes
N18.x
N17.9
to specify the stage of CKD when acute on chronic renal failure is present.
Differential Codes
N18.9
N18.9
when only chronic kidney disease is present without an acute component.
N18.4
N18.4
for severe CKD with GFR 15-29 mL/min/1.73 m².

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Nephrology

Specialty Applications

  • This diagnosis applies to patients with a known history of chronic kidney disease who present with acute renal failure.
  • Patient populations include adults with risk factors such as diabetes, hypertension, or prior renal impairment.
  • Clinical settings include inpatient hospital admissions, outpatient nephrology clinics, and emergency departments.
  • Specialty-specific applications are primarily in nephrology, but may also involve primary care and emergency medicine.
  • Treatment contexts include management of acute complications and planning for renal replacement therapy if necessary.

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Template 1

Template: 'Patient diagnosed with acute on chronic renal failure based on elevated creatinine levels and history of CKD.'

Template 2

Template: 'Clinical presentation consistent with acute on chronic renal failure including fatigue and decreased urine output.'

Template 3

Template: 'Diagnostic criteria met as evidenced by serum creatinine increase and prior CKD diagnosis.'

Template 4

Template: 'Treatment plan initiated for acute on chronic renal failure with dialysis and fluid management.'

Template 5

Template: 'Follow-up care for acute on chronic renal failure including monitoring of renal function and electrolytes.'

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What documentation is required for this diagnosis?

Documentation must include the patient's history of chronic kidney disease and current acute symptoms.

How does this differ from similar diagnoses?

Acute on chronic renal failure indicates a patient with pre-existing chronic kidney disease experiencing an acute decline.

What are common billing considerations?

Ensure that the diagnosis is well-supported by clinical documentation to optimize reimbursement.

What procedures are typically associated?

Commonly associated procedures include dialysis initiation and renal function monitoring.

Are there any quality reporting implications?

Quality measures may include tracking renal function and patient education on disease management.