A standard twin mattress is 39 by 75 inches. A king is 76 by 80 inches. This means that a headboard for a king bed is going to be about 76 inches or wider, plenty wide enough to go along the length of a twin bed. Headboards are often slightly wider than the bed for which they are made.
Hemoglobin, Hematocrit, Blood Count. In order to donate blood, a woman must have a hemoglobin level of at least 12.5 g/dL, and a man must have a hemoglobin level of at least 13.0 g/dL. For all donors, the hemoglobin level can be no greater than 20 g/dL.
Donated blood is carefully tested and tracked. It is very rare to get a disease through a blood transfusion. Getting the wrong blood type by accident is the main risk in a blood transfusion, but it is rare. For every 1 million units of blood transfused, getting the wrong blood type happens, at the most, 4 times. Transfusion with the wrong blood type can cause a severe reaction that may be life-threatening. Some people bank their own blood a few weeks before they have surgery.