Urinary proteome analysis and the management of ureteropelvic junction obstruction.

Ureteropelvic junction obstruction (UPJO) detected prenatally may over time deteriorate and require surgery, improve, or remain stable, and it may take upwards of 3 years for its natural history to unfold. Clinical decisions for or against operative corrections are usually based on scintigraphy follow-up studies. A non-invasive method for facilitating clinical decisions has recently been presented: urinary proteome analysis utilizing capillary electrophoresis mass spectrometry (CE-MS) has been shown to predict the outcome of UPJO in newborns. The group that developed this assay has now validated their seminal findings and extended the investigations to older age groups (this issue). The results of the blinded analysis correctly identified patients with UPJO who underwent surgery with a sensitivity of 83% (5 of 6 patients) and a specificity of 92% (12 of 13 patients) in infants up to 1 year of age. The validity of the analysis was poor in children >1 year of age with unilateral UPJO. A large number of patients will be needed to answer the question of to what extent the normal variability of urinary proteomes overlap with the variability of the pattern in UPJO beyond early infancy.