Scientists have developed a fully automated ‘micro-lab’ that can quickly and reliably determine a patient’s blood type.
Created by a team of researchers at Japan’s Tokyo University of Science, the novel ‘lab-on-a-chip’ is expected to change the way emergency medical support is given and reduce the costs of blood testing.
Blood transfusion, if performed quickly, is a potentially life-saving intervention for someone losing a lot of blood. However, blood testing methods are currently non-portable, have high personnel cost, and can take over half an hour to yield results. This can lead to potentially life-threatening complications in emergency situations.
Blood comes in several types, some of which are incompatible with others. Transfusing an incompatible blood type can cause serious harm to a patient so knowing their blood type is critical before a transfusion can be performed.
Lead researcher Dr Masahiro Motosuke said: “The device can shorten the time it takes to determine patients’ blood type which has the potential to save lives. The chip is able to complete the full blood testing process itself, which enables emergency doctors or nurses to perform the test there and then.
There are four major blood types: O, A, B, and AB. These types differ based on the presence or absence of structures called A antigens and B antigens. Blood can be further divided into positive and negative types based on the presence or absence of D antigens.
Medical professionals usually tell a patient’s blood type with tests involving antibodies against the A and B antigens. When antibodies recognize the corresponding antigens, they bind to them, causing the blood cells to clump together and the blood to coagulate.
Dr Motosuke said: “Most hospitals and clinics favour the traditional method of blood testing due to the complexity of new methods and a lack of connections between scientists and doctors.
“In our study, we communicated with doctors and designed the device to satisfy their needs. This made it possible for us to create a user-friendly device from a doctors’ perspective.”
The chip contains a micro-sized “laboratory” with various compartments through which the blood sample travels and is processed. The user simply inserts a small amount of blood, presses a button, and waits approximately five minutes for the result.
Inside the chip, the blood is diluted with a saline solution and air bubbles are introduced to promote mixing. The diluted blood is transported to a homogeniser where further mixing bubbles yields a uniform solution.
Portions of the homogenized blood solution are introduced into four different detector chambers. Two chambers each contain reagents that can detect either A antigens or B antigens. A third chamber contains reagents that detect D antigens and a fourth chamber contains only saline solution, with no reagent, and serves as a negative control chamber.
Antigen-antibody reaction will cause blood to coagulate, and by looking at which chambers have coagulated blood, the user can tell the blood type and whether the blood is positive or negative.
Dr Motosuke said: “The advancement of simple and quick blood test chip technologies will lead to the simplification of medical care in emergency situations and has the potential to greatly reduce costs and necessary labour.”
Dr Motosuke speculates that the portable nature of the chip will also allow for its use during aerial medical transport and in disaster response settings.