I have donated platelets in the past. I currently can't donate platelets any longer due to antibodies in my blood that have the potential to cause TRALI in some patients. I can still give my red cells, though. Also, I have been employed by a blood center for the past 5 years. I would like to clear up some misconceptions about donating:
1. If you donate in a "plasma center" your blood goes to companies to make cosmetics and other products. It is not transfused to people because the FDA believes that if people are paid to donate then they would not be truthful on the questionnaire therefore potentially making the blood supply unsafe.
2. In my blood center if you have acupuncture you can donate as long as they are single use needles or if they are your own personal needles.
3. There are currently 32 states who let you donate if you've had a tattoo in the last year. These states regulate their tattoo facilities. If you received your tattoo in a state that regulates their tattoo facilities and your tattoo is clean dry and pain free then you should be able to donate blood. If you receive it in one of the 18 states who do not regulate their tattoo facilities, another country, or you have it done in someone's home then you have to wait 12 months. Also, piercings are fine as long as its a sterile single use needle.
4. There are very few medications that prohibit you from donating, you can even donate on coumadin as long as your levels are stable. Examples of meds that prohibit you from donating are accutane, proscar, propecia, avodart etc. After you stop taking them for a certain period of time you can resume donating. These drugs are prohibited because the cause birth defects and they may potentially be transfused to someone who is pregnant.
Less than 5% of the population who is eligible to donate actually donate. Some don't ever attempt because of misconceptions.