Prerenal Kidney Failure: Sensitivity and Specificity

Introduction: Acute kidney failure is generally divided into 3 categories: renal, pre-renal, and post-renal causes. Pre-renal causes are those that result from hypoperfusion of the kidneys, principally hypovolemia and cardiogenic shock.

The most common causes of ARF are prerenal failure and ATN.

Another reference study is Ann Intern Med. 1978 Jul;89(1):47-50 PMID: 666184.

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The sensitivity and specificity of findings for Prerenal Kidney Failure are listed below. See the left navigation bar to change the display.

Sensitive and Specific Findings

Fractional Excretion of Urea

89.6%

96%

FEurea < 35%

including patients on diuretics. Patients with diuretics only had sens = 88.9%; without diuretics sens = 90%.

Study: Kidney Int. 2002 Dec;62(6):2223-9. PMID: 12427149

Specific Findings

Finding	Sensitivity	Specificity	Comments, Study
Fractional Excretion of Sodium	76.6%	96%	ratio < 1% including patients on diuretics. Patients with diuretics only had sens = 48%; without diuretics sens = 92%. Study: Kidney Int. 2002 Dec;62(6):2223-9. PMID: 12427149
Urine Sodium to Potassium Ratio	66.2%	92%	ratio < 1 including patients on diuretics. Patients with diuretics only had sens = 41%. Study: Kidney Int. 2002 Dec;62(6):2223-9. PMID: 12427149
Urine Creatinine to Plasma Creatitine Ratio	80.5%	88%	including patients on diuretics. Patients with diuretics only had sens = 63%. Study: Kidney Int. 2002 Dec;62(6):2223-9. PMID: 12427149

Sensitive Findings

Elevated BUN to Creatinine Ratio

87%

80%

ratio >15

including patients on diuretics. Patients with diuretics only had sens = 85%.

Study: Kidney Int. 2002 Dec;62(6):2223-9. PMID: 12427149