The Importance of Accurately Assessing Renal Function in the Neonate and Infant.

Measuring renal function in neonates and small infants is important to ensure that drugs are safely dosed and to detect acute kidney injuries early on. Serum creatinine (Cr) remains the most widely used marker, but its shortcomings are particularly important in neonates. For example, neonatal Cr largely depends on maternal renal function for at least the first 72 h of life. Novel approaches for assessing neonatal renal function include cystatin C and beta-trace protein. Another way to assess renal function is to measure renal volume by ultrasound. Although this approach may assess neonatal nephron endowment, it is insensitive to the postnatal adaptation of renal function in term and preterm neonates. The purpose of this review is to summarize what is known about measuring renal function in term and preterm newborns, and to summarize existing knowledge gaps, including a description of steps to take to close these gaps.