Serum cystatin C during 30 postnatal days is dependent on the postconceptional age in neonates

Abstract

The reference level of serum CysC was determined according to postnatal age and PCA. As the reference CysC level was dependent on gestational age and PCA, consideration of these parameters is warranted when assessing CysC levels in neonates.

Cystatin C adaptation in the first month of life

“…Je-Hyan Lee et al [20] have made a significant contribution towards closing the knowledge gap of cystatin C concentrations in the first month of life, despite the many limitations of their study. Further work and a coordinated effort across the globe is needed to develop a useful tool using the Box-Cox transformation of normal cystatin C data in infants to generate appropriate LMS charts for the calculation of age-independent percentiles that will enable accurate determination of the cystatin C percentiles based on postconceptional and postnatal age.…”

“…Interestingly, when all groups were analyzed separately and longitudinally, the cystatin C values can be seen to have increased slightly (Fig. 1, derived from Table 2 in the article of Je-Hyan Lee et al [20]). The slope of the regression line of the averages increases significantly in the extremely preterm group.…”

“…The undersigned call for a multicenter collaboration to identify all infant cystatin C measurements in healthy children or children without any obvious disease or nephrotoxic medication or dehydration to generate these percentiles. Some of the measurements obtained by Je-Hyan Lee et al [20] can be included. We suggest that the International Pediatric Nephrology Association could play a key role in coordinating such efforts.…”

“…However, pediatric reference intervals of cystatin C beyond 72 h postpartum to 1 year of age have to date lacked the necessary high resolution of post-conceptual age that is necessary to assess the rapid ontogeny of nephron recruitment in the first few months of life [3,5,18,19]. In that context, we are delighted to see an important attempt at closing the knowledge gap, at least for the first 30 days of life, in the study of Ji-Hyun Lee and coworkers in this edition of Pediatric Nephrology [20].…”

A step forward towards accurately assessing glomerular filtration rate in newborns

“…Currently, the most reliable eGFR formulae in children use CysC alone or in combination with Cr and/or urea [23]. Je-Hyan Lee et al [24] recently made a significant contribution to advancing our knowledge of CysC concentrations in the first month of life [25]. A suitable formula for calculating eGFR based on neonatal CysC has, however, been elusive.…”