[Creatinine of 250 micro mol/l: what should be done?]

This article aims at guidelines for evaluation of an accidentally detected increase of creatinine levels in serum and the decision if and when hospitalisation is mandatory. Hospitalisation is indicated when the general condition is poor and clinical signs of uremia like pericarditis, encephalitis, pulmonary edema with cliguria or anuria and severe hyperkalaemia or metabolic acidosis exist. In other cases an outpatient evaluation is possible yielding often information on preexisting risk factors, that may lead to functional renal failure, by history and clinical investigation. Furthermore assignment of the actual renal failure to a prerenal, renal or postrenal cause, usually by means of ultrasound and therapeutic consequences are demonstrated. A tabular overview on pathogenesis and gradation of various forms of acute renal failure and their identification by findings in urine sediments and/or chemical urine analysis is given.