A new blood test that is being developed by researchers has the possibility to revolutionise medicine in areas where it is difficult for health services to get to and areas where the traditional methods of blood typing may not be possible. If a blood transfusion occurs and the blood type of the donor does not match that of the recipient, it can be life-threatening as you could have a reaction meaning your immune system will begin to attack and destroy the blood of the donor. One problem that usually arises is that not everyone knows what type their blood is unless they have it tested, the four different types of blood for humans (A, B, AB and O) are categorised by the different antibodies and antigens found in the blood.
The more traditional methods for blood typing that are generally used involves a trained member of staff in a lab using a centrifuge to separate the blood in to different layers, this isn’t always possible in some places due to lack of equipment and can often take a long time. The new method being developed involves a special paper, Bromocresol Green dye and drops of blood from the person wishing to be tested. The use of Bromocresol Green dye is perfect as it fixes the problem of requiring specialist equipment and trained staff.
In the new test, the paper changes colour in the presence of different combinations of antibodies and antigens from the blood and the test works as follows. The test requires a piece of equipment with two ends, on the left side of the equipment the person must put a solution containing antibody A and for the right side, the person must do exactly the same except this time use a solution containing only Antibody B. A drop of blood must be added to the centre of the equipment, followed by a drop of the Bromocresol Green dye. The mix of dye and blood will travel down the piece of equipment until it comes in to contact with the antibody solutions on either side. Then blood type be determined in the following ways:
For type A, the left solution containing Antibody A would turn brown in colouration and the right solution containing Antibody B would turn teal in colouration. For type B, the left solution containing Antibody A would turn teal in colouration and the right solution containing Antibody B would turn brown in colouration. For type AB, both the right and left solutions would turn teal in colouration. For type O, both the left and right solutions would turn brown in colouration. Traditional methods can take as long as several hours however this new method can produce a result in 30 seconds. This reduction in time can sometimes be the difference between life and death.
Of the 3,550 samples that scientists tested on, they had an accuracy of 99.9%. However, although it seems as though this test is ready to be released, more testing is required to provide users insurance that the test will work under different conditions in different environments. As the test purely relies on colour change, as long as users understand what the change in colour means, almost anyone can use it and it could revolutionise point of care medicine.