What are the diagnostic criteria for acute kidney injury?
The diagnosis of acute kidney injury (AKI) requires integration of clinical presentation, laboratory tests, and imaging studies. However, standardized clinical diagnostic criteria for AKI remain incompletely unified. According to the most recent Clinical Practice Guideline for AKI established by the Kidney Disease: Improving Global Outcomes (KDIGO) initiative, AKI may be diagnosed if any one of the following criteria is met:
1. An increase in serum creatinine of ≥0.3 mg/dL (≥26.5 µmol/L) within 48 hours;
2. A confirmed or presumed increase in serum creatinine of ≥50% (i.e., 1.5-fold from baseline) within 7 days; or
3. Markedly reduced urine output—defined as urine volume <0.5 mL/kg/hour—for a duration of ≥6 hours.