Pavlaki A, Printza N, Farmaki E, et al. - Researchers undertook this prospective case-control study to determine whether the discrimination of surgical cases of ureteropelvic junction obstruction (UPJO) from non-surgical cases is possible by evaluating urinary levels of Neutrophil Gelatinase-Associated Lipocalin (NGAL) and serum levels of cystatin C and whether these could identify earlier impairment of renal function. They evaluated biomarkers in age-matched groups of 22 infants with surgical UPJO, at initial diagnosis and 12 months after surgery, in 19 infants with non-surgical UPJO and in 17 controls. They calculated the estimated glomerular filtration rate depending on serum cystatin C levels. Findings are suggestive of the ability of NGAL and cystatin C in differentiating between patients who underwent surgical treatment and healthy controls. A significant improvement in their postoperative levels was also suggested.