Red blood cell loss, such as prior to an operation. Before blood is given, a small sample of the recipient's blood is tested with the transfusion in a process known as cross-matching. In addition to the transmission of infection, certain types of transfusion reaction. In 2008 it was reported that human embryonic stem cells had been successfully coaxed into becoming red blood cells in the lab. The difficult step was to induce the cells to eject their nucleus; this was achieved by growing the cells on stromal cells from the bone marrow. It is hoped that these artificial red blood cells can eventually
Blood red wound, and it does not change color upon exposure to air. The color "blood red", therefore, covers both these states: the darker deoxygenated color and the brighter oxygenated one. Also, dried blood often has a darker, rust-colored quality: all dried blood has been oxygenated and then desiccated, causing the cells within it to die. This blood is often darker than either shade of red that can be seen in fresh blood. In the RGB color spectrum blood red often consists only of the color red, with no green or blue component; in the CYMK color model blood red has no