A new versatile paper-based test developed by Chinese scientists can perform blood group tests quickly and accurately without the need for any specialized equipment. The new paper test is capable of identifying a patient’s blood type — A, B, AO or O — with 99.9 percent accuracy in less than half-a-minute.
Unlike conventional micro-plate or gel-column blood-grouping tests, which are technically demanding and slow to return results, the easy-to-interpret paper test classified samples into the common ABO and Rh blood groups in less than 30 seconds after only two simple steps. The only inconsistencies occurred in trials involving highly uncommon blood types.
To create the test, Dr. Zhang and his colleagues at the Third Military Medical University in China took advantage of chemical reactions between blood serum proteins and the widely-available dye, bromocreosol green.
The researchers applied a small sample of the dye onto a test-strip containing antibodies that recognized different blood type markers (or antigens). The results appeared as visual color changes — teal if a blood group antigen was present in a sample and brown if not. With slightly more time (but still in less than two minutes) the assay was able to identify multiple rare blood types.
Moreover, when the researchers incorporated a separation membrane to isolate plasma from whole blood, they could simultaneously identify specific blood cell antigens and detect antibodies in the plasma, based on how the blood cells clumped together (also known as forward and reverse typing), all without the use of a centrifuge.
“The rapid turnaround time of the test could be ideal for resource-limited situations, such as war zones, remote areas, and during emergencies,” said Dr. Zhang.