CST3 and hematocrit: At 6 months after discharge from the neonatal intensive care unit, it is suggested that laboratory tests with serum creatinine and/or cystatin C, and microalbuminuria be performed, and then the periodicity of these tests should be adjusted according to these results or the appearance of comorbidities: history of AKI in the neonatal period or during infancy, HT, obesity, and ultrasound abnormalities.