British scientists claim to have developed a new technique that can tell whether the blood used for transfusions is old or new,thus providing a cheap and an effective way to monitor the quality of blood supplies.
Even with preservatives,blood stored in banks ages,resulting in biomaterials leaking from the red blood cells and subsequent changes to cell properties and function. Currently,blood stored in a special medium can be used for transfusion for up to 42 days,but monitoring of the blood varies.
Now,a team at University of Cambridge has developed the new method which can determine the significant differences between new and old red blood cells used for transfusions,the ‘Journal of Cellular and Molecular Medicine’ reported.
“Recent trials on cardiac surgery patients involving over 40,000 patients showed that transfused blood which was older than 14 days produced serious side effects. The side effects of transfusing old blood are thought to result in acute lung injury and adverse effects of the immune system.
“In severe trauma patients,transfusion of blood stored for more than 28 days doubled the incidence of deep vein thrombosis and increased death secondary to multiple organ failure.
“Our research will hopefully highlight the significant differences between old and new blood used in transfusions as well as the possibility of using our technique to quickly and cheaply monitor blood supply quality,” Jay Mehrishi,who led the team,said.
According to the scientists,the electrical properties of red blood cells have previously been used to distinguish between foetal and adult haemoglobin,and the mutated form of haemoglobin found in sickle cells from normal haemoglobin.
Now,using the unique electrical properties of red blood cells,the scientists used fluorescence from positively charged quantum dots which had been bound to electrical charges on negatively charged cells to discriminate between old cells and young cells.
On young red blood cells the fluorescence was intense bright,indicating that the surface architecture was intact. Whereas on the older red blood cells,the fluorescence was zero and the cells shown significantly darker,indicating that there had been a substantial loss of the electrical charges,indicating the cell membrane integrity had been compromised.
It is recognised that such damaged cells are not useful for transfusions because the body eliminates them from circulation quite quickly,say the scientists.
In addition to its use as a monitoring technique for the quality of blood stored in blood banks,Dr Mehrishi believes that it could also be used to ensure a high quality of “cleaned up” blood which is of immense practical clinical importance worldwide.
“These results are not only of theoretical interest but are also of immense practical clinical value. Our novel approach is also likely to be of practical value in clinics before,during and after therapy,for problems as circulatory disorders,abnormal red cells,” said Dr Mehrishi.