What are the RIFLE criteria for acute kidney injury (AKI)?

Updated: Aug 07, 2018
  • Author: Piper Julie Hughes, MD, MS; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Answer

In 2002, the Acute Dialysis Quality Initiative (ADQI) was created with the primary goal of developing consensus and evidence-based guidelines for the treatment and prevention of acute kidney injury (AKI). The first order of business was to create a uniform, accepted definition of AKI; hence, the RIFLE criteria were born (see the table below). RIFLE is an acronym of Risk, Injury, and Failure; and Loss; and End-stage kidney disease.Table 1. RIFLE Classification System for Acute Kidney Injury [6]

Table. (Open Table in a new window)

Stage

GFRa Criteria

UOb Criteria

Risk

SCrc increased 1.5-2 times baseline

or

GFR decreased >25%

UO < 0.5 mL/kg/h < 6 h

Injury

SCr increased 2-3 times baseline

or

GFR decreased >50%

UO < 0.5 mL/kg/h >12 h

Failure

SCr increased >3 times baseline

or

GFR decreased 75%

or

SCr ≥4 mg/dL; acute rise ≥0.5 mg/dL

UO < 0.3 mL/kg/h 24 h

(oliguria)

or

anuria 12 h

Loss of function

Persistent acute renal failure: complete loss of kidney function >4 wk (requiring dialysis)

ESRDd

Complete loss of kidney function >3 mo (requiring dialysis)

a GFR = glomerular filtration rate.

b UO = urine output.

c SCr = serum creatinine.

d ESRD = end-stage renal disease.

Note: Patients can be classified either by GFR criteria or by UO criteria. The criteria that support the most severe classification should be used. The superimposition of acute on chronic failure is indicated with the designation RIFLE-FC; failure is present in such cases even if the increase in SCr is less than 3-fold, provided that the new SCr is greater than 4 mg/dL (350 μmol/L) and results from an acute increase of at least 0.5 mg/dL (44 μmol/L).

When the failure classification is achieved by UO criteria, the designation of RIFLE-FO is used to denote oliguria. The initial stage, "risk," has high sensitivity; more patients are classified in this mild category, including some who do not actually have renal failure. Progression through the increasingly severe stages of RIFLE is marked by decreasing sensitivity and increasing specificity.

A recent study to assess RIFLE urine output criteria based on creatinine concentrations for the development of contrast- induced acute kidney injury (CA-AKI) in intensive care (ICU) patients found low predictive value. The authors concluded that there was limited use for assessing the effects of therapeutic interventions on the development and progression of AKI in this population. [7]


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