Abstract: A method for predicting a high-grade vesicoureteral reflux in a patient includes the steps of measuring the serum concentration of procalcitonin in a biological sample, assigning a procalcitonin value, looking for a dilation of one or two ureters shown on an echographic image of a kidney, assigning an echographic value, and combining the values by two mathematical equations with the definition of a threshold above which the patient is considered at risk for vesicoureteral reflux. A kit including a device for measuring the procalcitonin concentration and device for measuring the cross-section of the ureter is described.