Add Yahoo as a preferred source to see more of our stories on Google. A person's blood type is determined by "the presence or absence of certain antigens – substances that can trigger an immune ...

Knowing your blood type is crucial medical information, but unless you've given blood before you might not be sure what yours is. I realized this when I was asked for mine while filling out paperwork ...

Christine Helms does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...