Whole blood can be safely stored for only a few days. That had always meant that blood donations had to come from local sources and be given at the time of need. Blood couldn’t travel long distances. People with unusual blood types often had to do without during surgery and suffered accordingly.
Charles Drew discovered the process of separating blood into red blood cells and blood plasma. This discovery greatly extended the shelf life of stored blood and has saved thousands, and probably millions, of lives. Drew’s discovery made blood banks practicable. His process and discovery are still used by the Red Cross today for its blood donation and storage program.
The idea of blood transfusions is thousands of years old and was practiced by Roman doctors. However, there was a problem: many patients died from the transfusion. No one could understand why this happened until Karl Landsteiner discovered the four blood types in 1897 (A, B, O, and AB). By 1930, other researchers had further divided these groups into eight types by identifying the RH factor for each group (e.g.: O+, O-, A+, A-, etc.).
With these discoveries, blood transfusions became virtually 100 percent safe. But now hospitals had to store eight kinds of blood in order to have whatever supply was needed for surgeries. However, most donated blood had to be thrown away because it spoiled before being used. Some common blood types ran out and patients faced grave danger when they had to undergo surgery without it. Blood storage became a critical problem for surgeries and hospitals in general.
Charles Drew was born in mid-summer in 1904 in Washington, D.C. An all-American football player at Amherst College, Drew chose to study medicine rather than play sports.
In 1928 Drew was accepted into medical school at McGill University in Canada (one of the few university medical schools to accept blacks in 1928). There Drew studied under Dr. John Beattie, a visiting professor from England. In 1930 Beattie and Drew began a study of ways to extend safe blood storage time from the existing limits of between two and six days. This short shelf life drastically limited available blood supplies.
Drew graduated in 1935 and left the university with little progress having been made. In 1938, he took a research position at Columbia University in New York City and continued his blood research. There, he developed a centrifuge technique that allowed him to separate red blood cells from the rest of blood. This “rest” he called blood plasma.
He quickly determined that red blood cells contain the unique substances that divide blood into the eight blood types. Blood plasma, however, was universal. No matching was necessary. Blood plasma from any donor was compatible with any recipient. This made plasma especially attractive for blood supplies.
Drew tested plasma and showed that it lasted far longer than whole blood. Next, he showed that red blood cells, separated from plasma, also could be stored longer than whole blood.
In 1939 Drew discovered that plasma could be dehydrated, shipped long distances, and then safely rehydrated (reconstituted) by adding water just before surgery. Suddenly blood donors could be thousands of miles from recipients.
In 1940 Drew published his doctorial dissertation. In it he presented his statistical and medical evidence that plasma lasted longer than whole blood and detailed the process of separating blood into red blood cells and plasma and the process for dehydrating plasma. It served as a blueprint for managing the national blood supply. In 1941 Drew created the first “bloodmobiles”, trucks equipped with refrigerators, and started the first blood drive (collected for British airmen and soldiers).
Drew had discovered plasma and how to safely store blood for long transport, and had created a practical system of blood banks and bloodmobiles to collect, process, store, and ship blood wherever it was needed. Finally, blood transfusions were both safe and practical.
Is all blood red? No. Crabs have blue blood. Their blood contains copper instead of iron. Earthworms and leeches have green blood; the green comes from an iron substance called chlorocruorin. Many invertebrates, such as starfish, have clear or yellowish blood.