Hello,

I've been donating plasma for 3 years and now my left arm is starting to become numb if I lean on it too long. I'm not having problems with my other arm which may be because I only donate with my left arm. My question is... is my left arm becoming numb because of the donating?

No, this should have no bearing on nerve endings and feelings.

I will say you can change arms, I rotate arms for donations just to change off. But if you lean on a nerve any arm will become numb, like your leg going to sleep in in a certain position