I stopped giving plasma so I could go back to do a study, same one you are doing I think. When you do plasma you verify that you haven't done any research studies for at least a year. You could actually go to jail if they found out you gave plasma after doing a research study. You could be putting sick people at great health risk by giving tainted plasma products to them. If you have no morals and don't care about that then another reason not to do both is you could get a bruise on your arm from doing the study and a bruise disqualifies you from giving plasma. You could also have to lie to a research nurse about why you have a bruise on your arm. They may think you are doing another study. You could get banned from future studies. You should choose one or the other, plasma OR studies, not both.