In clinical practice, there is no such thing as unicorn blood group because there are various blood groups in human beings, and there are two widely used in clinical practice, one is the ABO blood group system and the other is the RH blood group system. No matter which blood group system is used, it is named according to the antigens contained on the surface of the red blood cell membranes. For example, in the RH blood group system, if the D antigen contained on the surface of the red blood cell is RH positive, and the absence of D antigen is RH negative. At the same time, in our population, RH-positive people account for the vast majority of people, RH-negative people are very few. In the ABO blood type, the same kind of red blood cell surface contains A antigen is A blood type; contains B antigen is B blood type; both contains A antigen, and contains B antigen is AB blood type; neither A antigen, nor B antigen is O blood type. There is no such thing as unicorn blood among human blood types.