Inclusion Criteria:  The patient or their representative must have given their free and informed consent oral consent The patient must be a member or beneficiary of a health insurance plan Patient living in the Gard, France  Patient with abnormal dose:  Severe grade 4 or 5 CKD suspected in front of a GFR <30 mL / min / 1.73m2 persisting during hospitalization. Acute kidney injury > stage 1 defined by an increase in serum creatinine of at least 100% in less than 7 days or a threshold greater than 354 µmol / l.  Exclusion Criteria:  The subject is participating in another category I interventional study, or is in a period of exclusion determined by a previous study It is impossible to give the subject or their representative informed information The patient is under safeguard of justice or state guardianship Patient is pregnant, parturient or breastfeeding. Patient unable to express consent Patient with Stage 1 Acute kidney injury defined by an increase in serum creatinine of more than 26 µmol / l in less than 48 hours or a 50% increase in serum creatinine within 7 days. Patient with stage 1 to 3 CKD (glomerular filtration rate (GFR)> 30 mL / min / 1.73m2)