I have Masters degree with Distinction and Student of the Year Prize in Corrosion of Engineering Materials from Imperial College London, first degree in Chemistry from University of Central Lancashire and also did Technology, Material Science and Engineering and Mathematics from the Open University.
In areas where tattooing is not as closely monitored, people are asked to wait for 12 months to give blood after getting a tattoo. This waiting period ensures that the donor is free of any potential blood-borne diseases which could have been passed on unsanitary equipment.
So, whole blood donors are generally required to wait some two to three months to donate a second time. [white cells and plateletes generally renew within a week ] With plasma donation it's a bit different. Unlike whole blood donation, you will have your red blood cells and/or platelets and white cells returned to you.