I had my yearly fasting blood test and then on top of that an extensive allergy food blood test, which took a lot of blood. It will show all sorts of foods and preservatives I'm sensitive to that may cause many of my health problems. The trouble I had was I started getting light headed and thought I was going to pass out, so I had to sit there for awhile until I felt better, and by the time I walked to the elevator it happened again, so I had to stop and lower my head until it passed. I finally made it home but I drove like a snail and prayed all the way home. God answers prayer as he got me home safely, and after I ate something and felt better, but still had a few moments of "hang on to something so you don't fall over and break something with your 5 feet 11 inch body!!!" I have a lot of blood drawn all the time and this was the first time I felt like this. Bummer.