What is the inpatient workup for Acute Kidney Injury (AKI)?

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Last updated: February 12, 2025View editorial policy

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From the Guidelines

The inpatient workup for Acute Kidney Injury (AKI) should include a thorough history, physical examination, and laboratory analysis of blood and urine to identify the underlying cause of AKI, as the treatment approach varies depending on the etiology 1.

Key Components of the Workup

  • Laboratory tests:
    • Blood tests: serum creatinine, blood urea nitrogen, complete blood count, and differential
    • Urine tests: microscopy for casts and epithelial cells, chemistry, and biomarkers
  • Imaging studies may be indicated to evaluate for postrenal causes of AKI, such as ureteral obstruction
  • Renal biopsy may be necessary to differentiate between nephritic and nephrotic syndromes

Importance of Early Identification

Early identification of the cause of AKI is crucial, as it allows for timely intervention and management, which can improve patient outcomes and reduce the risk of progression to chronic kidney disease (CKD) 1.

Classification of AKI

AKI can be classified into three categories:

  • Prerenal: impaired blood flow to the kidneys, which can be caused by hypotension, hypovolemia, or decreased cardiac output
  • Renal: damage to the renal parenchyma, which can be caused by diseases such as vasculitis, acute tubular necrosis, or glomerulonephritis
  • Postrenal: obstruction of the urinary tract, which can be caused by ureteral, bladder, or urethral obstruction 1

From the Research

Inpatient Workup for Acute Kidney Injury (AKI)

The inpatient workup for AKI involves several key steps, including:

  • Determination of baseline performance to benchmark quality efforts 2
  • Timely recognition of AKI, which is crucial for improving patient outcomes 2, 3
  • Appropriate diagnostic workup to identify the underlying cause of AKI 2, 3
  • Implementation of known interventions to limit progression and severity, facilitate recovery, and mitigate AKI-associated complications 2, 4
  • Fluid and electrolyte management, which is essential for AKI management 5, 6
  • Consideration of kidney replacement therapy (KRT) for patients who do not respond to conservative management 5, 4, 6

Key Components of AKI Management

The management of AKI in hospitalized patients should prioritize:

  • Identification of achievable goals likely to have the highest impact according to the setting and context 2
  • Use of quality metrics to evaluate the quality of AKI management, such as improvement in timely recognition, appropriate diagnostic workup, and implementation of known interventions 2
  • A multidisciplinary approach to care, involving experts from various fields to discuss evidence and achieve consensus on recommendations for AKI-related quality indicators and care processes 2

Diagnostic Workup and Treatment

The diagnostic workup for AKI should include:

  • Laboratory tests to assess kidney function, such as serum creatinine and urine output 3
  • Identification of the underlying cause of AKI, which can include sepsis, cardiorenal syndrome, and urinary tract obstruction 3
  • Treatment strategies that target the underlying cause of AKI and avoid further insults 6
  • Consideration of supportive care, including fluid management, vasopressor therapy, and KRT 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Acute kidney injury.

Lancet (London, England), 2019

Research

Acute kidney injury.

Nature reviews. Disease primers, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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