Researchers at the University of Alabama at Birmingham have found that the amount of proteins excreted in the urine of preterm infants with acute kidney injury, or AKI, is different from that excreted by infants with healthy kidneys.
The study, led by principal investigator David Askenazi, M.D., was published in the Clinical Journal of the American Society of Nephrology.
“The findings in this study could help physicians better diagnose kidney health in newborns,” said Askenazi, associate professor in the UAB Department of Pediatrics and director of UAB’s Pediatric and Infant Center for Acute Nephrology. “Having better diagnostic tests to diagnose kidney injury will have an important impact on how we care for infants and how we prognosticate outcomes, and will enable us to design studies to prevent and/or mitigate kidney damage in these very vulnerable babies.”
Improving the ability to diagnose AKI, a sudden decline in kidney function, is critical, as approximately 25 percent of preterm infants develop AKI. Compared to those without AKI, preterm infants with this common problem have a lower chance for survival, increased hospital stays and increased hospital expenditures. 
Importantly, premature infants are at high risk for chronic kidney disease, and AKI may be an important cause for this.
Investigators took a single drop of urine from 113 preterm infants and measured 14 urine proteins. The concentrations of many of these proteins, including cystatin c, neutrophil gelatinase-associated lipocalin, osteopontin, clusterin and alpha glutathione S-transferase, were higher in preterm infants who later showed abnormal kidney function, compared to their counterparts with normal function.
“Additional studies to determine how AKI contributes to chronic kidney disease in these newborns are underway,” Askenazi said. “Improving our ability to diagnose AKI accurately is critical to improving our understanding of the natural course of disease and developing strategies to improve outcomes.”
Study co-authors include Rajesh Koralkar, MPH, Neha Patil, M.D., Brian Halloran, M.S., Namasivayam Ambalavanan, M.D., and Russell Griffin, Ph.D.