Does plasma donation cause iron deficiency?  

It really shouldn't but small amounts of blood are lost with the pheresis machine so it may occur with frequent donation. I would make sure to check from time to time. There are only marginal amounts of Fe in plasma so infrequent donations are unlike to cause iron deficiency.

Most plasma donors in the USA are paid by fractionators/manufacturers such as CSL Plasma, and donate no more than twice per week. The collections are performed by plasmapheresis and the red cells are returned at the end of the procedure. But, as Dr. @Auerbach notes, sometimes small amounts of red ce...

I don't have too many patients who donate plasma rather than blood so not something I encounter in clinical practice typically