Measurement of Iohexol Plasma Clearance in Patients Leaving ICU After Acute Renal Failure

Inclusion Criteria: * ICU stay \> 7 days * Having presented during the stay renal failure stage 2 or 3 Kidney Disease Improving Global Outcomes (KDIGO) * Steady improvement of renal function before the ICU discharge : * Creatinine before ICU discharge \<110 µmol / L for women, \<130 µmol / L for men * No recourse to extra renal purification * Change in creatinine levels (ΔCréatinine) less than 20% over two measures spaced 24 hours within 48 hours preceding the discharge * Expected discharge ICU within 48 hours : * Glasgow score \> 13 * Lack of mechanical ventilation except home Noninvasive Mechanical Ventilation (NiMV) * Lack of use of catecholamine * No contra-indication for discharge according to physician in charge of the patient * Informed consent signed by the patient, where not possible by the person of trust or the family if present. Written consent by the patient will be obtained as soon as deemed possible. Exclusion Criteria: * Iohexol administration within 48 hours preceding the potential inclusion (imaging examination with X-ray contrast medium injection) * Iohexol administration planned within 24 hours after potential inclusion in the study * Known medical history of immediate allergic or delayed skin allergic reaction to injection of iodinated contrast material or any serious doubt on this medical history * Patient receiving from extra renal purification during ICU discharge * Chronic renal disease known (creatinine\> 110 µmol / L for women,\> 130 µmol / L for men) or creatinine clearance estimated less than 60 mL / min * Pregnancy or breastfeeding women * Patient under guardianship or safeguard justice known at the time of inclusion * Patient limitation care * Person not affiliated or not the beneficiary of a social security scheme