Hello and hope you are doing well.
As suggested it's unlikely that standing for long hours can cause proteinuria. It could be due to the kidney disease. Hope diabetes has been ruled out.
Hope this helped and do keep us posted.
no thisw will not cause foamy urine, I have stage 3 alos and have had foamy urine for some time, I call it beer head urine!!! it is a sign of kidney disease. I have also protein in the urine and that is also a classic symptom