Nope ! I wear diabetic socks all the time, specifically for that reason.
The renal panel is a good idea.

I'm really bad about getting bloodwork done, because its a PIA.
I can't get it done at my doc's, cause the lab in the building
doesn't accept my ins.
I have to go a 30 minute drive, across town to the closest
"LabCorp" to have blood drawn & I've been sitting on a lab requisition
since last Sept '07.
I've tried to go.... twice, but the wait was 2 hours or more each time, and I left. My lab work has to be a 12 hour fast, so I go early in the am, but have to get to work by 9. The lab opens at 7:30 and when I get there, there's already a line backed up. The lab is always short-staffed with the small waiting room over-flowed. So.... I've not been back. I probably have to get another requisition, since this probably has expired & they'll turn me away with one dated 9/2007. I'll ask my doc to include a renal panel too.
For me to get a simple blood draw, is a real pain in the BUTT !.

BTW, the swelling sensation, is just on the balls of my feet
and the fleshy bottom part of my toes (weird!),
not on the heel part, or the tops (instep), or at the ankles- at all !