Blood compatibility – it’s all in the genes!

In most developed countries safe blood transfusion is taken for granted. But blood grouping is a complex business, and not all blood groups are compatible. In order to check for compatibility, two cross-matching tests are carried out prior to transfusion – but these tests are based on technology that has not changed since the early days of blood transfusions.

Now a consortium called Bloodgen, led by the University of the West of England (UWE), Bristol, is nearing the end of a three-year project that aims to use genotyping to improve patient safety and blood transfusion compatibility. The project will include the launch of a CE-marked commercial product Bloodchip which will be sold to Blood Services worldwide. A Research TV film on the project, entitled ‘Compatibility – it’s all in the genes’ – can be seen at http://research-tv.warwick.ac.uk/stories/health/bloodgen/

Currently, the two blood groups are tested for routinely ABO and Rh (Rhesus). However there are 29 different blood group systems Not all blood groups are compatible and mixing incompatible groups can put some people at risk. Bloodchip tests for 9 of these systems, which includes all clinically relevant blood groups.

The blood group to which people belong depends on the combination of antigens built into their DNA and antibodies to antigens they have previously been exposed to. The genotyping test extracts DNA from blood and uses a gene chip, a small microscope slide capable of performing up to 300 reactions, to compare donated blood with that of a potential recipient.

Professor Neil Avent, director of UWE’s Centre for Research in Biomedicine and leader of the project said:

“Blood grouping at the moment uses antibodies that interact with proteins on the surface of cells. Genotyping is looking at the genes: our research looks at the blood group specific genes which vary from one individual to another. This is certainly a safer means of testing blood because of its comprehensiveness. The chip will embrace all blood groups that are clinically significant and we’ll be able to have those tested on a routine basis.

“The ultimate goal is that a new technology will come in and replace techniques that have been around for 100 years or so. Genotyping is incredibly accurate and could be used for a wide range of routine testing of patients in the near future.”