Photo by Graham Colm
Blood samples
Researchers say they have created a paper-based assay that provides “rapid and reliable” blood typing.
The team used this test to analyze 3550 blood samples and observed a more than 99.9% accuracy rate.
The test was able to classify samples into the common ABO and Rh blood groups in less than 30 seconds.
With slightly more time (but still in less than 2 minutes), the assay was able to identify multiple rare blood types.
Hong Zhang, of Southwest Hospital, Third Military Medical University in Chongqing, China, and colleagues described this test in Science Translational Medicine.
To create the test, the researchers took advantage of chemical reactions between blood serum proteins and the dye bromocreosol green.
The team applied a small sample of whole blood onto a test-strip containing antibodies that recognized different blood group antigens.
The results appeared as visual color changes—teal if a blood group antigen was present in a sample and brown if not.
The researchers also incorporated a separation membrane to isolate plasma from whole blood, which allowed them to simultaneously identify specific blood cell antigens and detect antibodies in plasma based on how the blood cells clumped together (also known as forward and reverse typing), without a centrifuge.
The team said the rapid turnaround time of this test could be ideal for resource-limited situations, such as war zones, remote areas, and during emergencies.
