mwilliam,
No, donating plasma would not cause you red blood cell to be elevated. I however do question the safety of donating plasma as frequently as you do. It is usually advisable to only donate plasma once a week and it is best to only donate once every two to three weeks. I would guess that your veins must be getting pretty scarred up. I used to donate plasma every three weeks and my veins got so scarred that I was restricted to using the machine that only requires one arm. I would alternate which arm was used, unfortunately, I am not a the best patient for blood draws. I am very patient, however, I have been known to have 4-5 tries to obtain a sample of blood or to have an iv placed.
I am sure that your doctor is going to be looking into the cause of your high red blood count, I can tell you that the treatment for such an disorder is frequent blood donations.
Let me know what you find out.
Brenda