I rate it on the pitting by how many seconds it takes to return to normal after an indent. If it takes 1-3 seconds I rate it a one, 4-6 seconds a two, more a three and after that I tell them how many seconds and say beyond a three.
Now I push down till a good blanch happens, then count...and I do it on multiple sites. I also take the time since I am there to feel for pedal pulses and let my MD know if I was able to find them easily or not...and I get lucky here because I know my patients well...if I can find them normally...if not I say that I don't know if they normally have easy to find pedal pulses.
Rating edema becomes natural to tell after a while I think...and with non pitting...well that is enough for me just to tell my MD's..."hey we have non pitting" and I describe skin tone, color, nailbeds, hair placement (that tells you volumes actually about circulation!), nail condition, temp of the extremity, any numbness/tingling, pain, changes in mobility...you name it (well I tell that for pitting too)! AND especially if there is skin damage r/t this! I have been told I am overly efficient by my other nurses..but the docs..they love me!!!!
But edema is my game really...I work at an assisted living facility where everyone seems to have a degree of CHF, or diabetes, or other conditions where edema is just fairly normal. SO is lasix..LOL! OH those poor folks...they may not know most of their meds..but they know that one..they call it the "pee like a race horse pill"...or "little, white, peeing all night" (my humor has been transfered to my clients..can you tell? LOL).
Did you know that lasix was actually made for race horses? Yeppers! It was produced to encourage lower water weight in horses so they were lighter...then a smart doc said..hmmmm fluid regulation..and the rest is history :). So when a client says "I am peeing like a race horse" tell them "yep...you are!!!!"...LOL!