What does some protein on a routine urine test of a child mean?

Hope is orthostatic. Orthostatic proteinuria is most common cause of urinary protein in a child. Thus child spills protein when they are up & about, not when recumbent. It's benign. Can be checked by having child urinate 2 hours after bed, then checking first A.M. Urine. Active proteinuria round the clock might be indicative of kidney disease, such as glomerulonephritis, and should be checked by pediatric nephrologist.