Every two seconds, someone needs blood in the U.S. A total of 36,000 units of red blood cells are needed every day. Yet, a staggering number of Americans don't know whether their blood type is A, B, AB or O, or something rare. Researchers at the Third Military Medical University in China have devised a paper strip test that will be able to verify your blood type in just 30 seconds.
“Blood type matching is important for pregnancy, blood transfusion, and bone marrow transplantation,” wrote the team, in the study published in Science Translational Medicine.
Typically, traditional blood typing takes up to 10 to 20 minutes, requiring the use of a centrifuge. This spins the blood and separates it into different components. Now, Chinese researchers used a common dye, bromocresol green, which interacts with blood, to determine blood type.
The paper test works by observing antigens — proteins that are located on the outside of red blood cells — and antibodies — proteins produced by the body to fight off foreign invaders in your blood on a thermometer-like device. People with type A blood contain red blood cells with A antigens; B with B antigens; AB with both; and O with neither. A blood type is determined to be "positive" or "negative" if a separate D antigen is present.
At the time of testing, the paper test will contain antibodies and blood, so when a drop of blood is placed, squares of color begin to form as the blood flows across the strip, and reacts with the antibodies. A teal square will show up if A, B, and D antigens are present, if not, a brown square will appear. For example, if you're type AB, in which both antigens are found on red blood cells, both solutions will turn teal, and type O, where no antigens are found, would turn both solutions brown.
The color change takes just a total of 30 seconds. However, for rarer blood types, such as U- Fy (a-b-); RzRz; Jk (a-b-); Di (b-); Dr (a-); Kpb-); and Vel-, this would take less than two minutes. This is still much faster than the traditional blood typing test. The study, conducted on 3,550 human blood samples, had a 99.9 percent accuracy rate.
“When translated to the assembly line and low-cost manufacturing, [our device] may be developed into a cost-effective and robust universal blood-grouping platform," said the researchers.
Availability of this test would ease the demand of blood type O. This type, specifically type O negative, is usually in short supply and in high demand by hospitals since it's the only universal blood type, according to the American Red Cross. Moreover, knowing your blood type will allow hospitals to get blood to you quickly, but for those with rare blood types, it can take hours or days to find. This is why, if you have a rare blood type, you can store it for future use.
The importance of knowing your blood type will help prevent a wrong blood type transfusion, which is potentially fatal.
Source: Zhang H, Qiu X, Zou Y et al. A dye-assisted paper-based point-of-care assay for fast and reliable blood grouping. Science Translational Medicine. 2017.