During the Medical History part of your donation process, the Historian will take a small blood sample from your finger to test your hemoglobin, which is the oxygen-carrying molecule in your red blood cells. In order to get an accurate sample of your hemoglobin level, your hands must be warm. Try rubbing your hands together, holding a warm drink, or running warm water over your hands before the finger stick. If your hands are cold, notify a staff member. If your hemoglobin is too low, you will not be able to donate blood that day. Please come back soon!