If your blood sample is being tested only for a complete blood count, you can eat and drink normally before the test. If your blood sample will be used for additional tests, you may need to fast for a certain amount of time before the test.
Michael Wood II, Purchaser, Retailer and Researcher of Mattresses and Sleep Products. A double and a full size are the same thing. Just different terminology. You'll find that a full size bed - through Google, etc - is 55 Wide x 75 Long. The mattress is usually an inch (or slightly more) smaller in each direction, so; your full mattress will normally measure at (average) 53.5 x 74 - the additional space is to insure that you have room to tuck sheets, etc.
edit Dimensions. Both full beds and twin beds are 75 inches (191 cm) long. They differ when it comes to width, however. At 54 inches (137 cm) wide, a full size bed is nearly as wide as a queen size bed. Twin beds are much narrower, measuring a mere 39 inches (99 cm) across. This video provides information on all bed sizes, including twin, full, queen, and king: