RIFLE Criteria for Acute Kidney Injury (AKI)
RIFLE Criteria for AKI
Serum Creatinine / GFR Criteria
Urine Output Criteria
RIFLE Class:
No AKI
No AKI
Does not meet RIFLE criteria for acute kidney injury.
Classifies severity of acute kidney injury, similar to AKIN Classification .
Formula
Selection of the appropriate criteria. For serum creatinine, GFR, and urine output, choose the criteria leading to the worst classification (e.g. if serum creatinine is at baseline but GFR is >50% below baseline, RIFLE Class is RIFLE-I). RIFLE Criteria Serum creatinine GFR Urine output R isk, RIFLE-R 1.5-2x above baseline >25% decrease below baseline <0.5 mL/kg/hr x 6 hr I njury, RIFLE-I >2–3x above baseline >50% decrease below baseline <0.5 mL/kg/hr x 12 hr F ailure, RIFLE-F (RIFLE-FO if oliguria) >3x above baseline, ≥4 mg/dL (350 µmol/L), or acute rise ≥0.5 mg/dL (44 µmol/L) >75% decrease below baseline <0.3 mL/kg/hr x 24 hr (oliguria) or anuria x 12 hrs L oss, RIFLE-L Persistent AKI (on renal replacement therapy for >4 weeks) E SRD, RIFLE-E End stage renal disease (on dialysis for >3 months)
Pearls / Pitfalls
Requires baseline serum creatinine, which is often not known in clinical practice. In CKD patients, baseline creatinine determined GFR of 75 mL/min/1.73 m² has low correlation with actual creatinine, resulting in of AKI incidence ( Lopes 2013 ). Developed using the MDRD GFR Equation , which is validated in CKD patients with stable renal function but not validated in AKI.
Advice
Remember that AKI may be present even with “normal” serum creatinine, if GFR is decreased, or if creatinine is significantly elevated above baseline.