What does protein in urine mean?
A bit late, but this is something everyone ought to know: The kidney is an ultrafiltration system. It regulates the level of the toxic by-product of protein breakdown (urea), plus sodium and choride ion and water levels in the blood. These are all very small chemicals. Sugar and especially proteins are much larger chemicals. If they appear in the urine, then the filter system is damaged - immediate medical intervention is required to find out the cause.
It is quite normal for humans to pass protein in their urine. However, large amounts of protein in the urine can indicate serious kidney problems which should be checked out by a doctor asap.
Mild frothing of urine is usual, but excess of frothing denotes protein leakage in urine.