Biomarkers have been found to help physicians diagnose and treat acute kidney injury.

Three protein measurements indicate who has a high risk of developing kidney injury after heart surgery, according to studies published in the Journal of the American Society of Nephrology.

"To date, these are the largest studies in adults and children comparing and validating the performance of three of the most frequently studied markers of kidney injury," said author Chirag Parikh, MD, PhD (Yale University School of Medicine).

The study had over 1,200 adults and 300 children undergoing heart surgery throughout North America. Urine and blood samples were collected to measure the levels of 3 proteins urine interleukin -18 (IL-18), urine and plasma blood and neutrophil gelatinase assisted lipocalin (NGAL), and assessed their ability to predict who will develop kidney injury after surgery.

Traditionally, kidney trouble is diagnosed by measuring the blood protein creatinine but the result takes time and does not report early kidney damage.

Risk of kidney injury was especially high, six times greater, for adults and children with the highest levels of urine IL-18. Plasma NGAL also predicted kidney injury in adults, NGAL were accurate predictors in children.

“Doctors may wish to measure these urine or blood proteins immediately after surgery to predict which patients are at high risk of developing kidney injury. These patients might benefit from kidney protective therapies.” said Parikh

The results could also transform the diagnosis of kidney disease, Parikh believes. "Developing markers of structural kidney damage, before kidney function fails, is a top priority,"