Type A RH negative blood is a specific categorization of the human blood type system. Type A blood means that the blood type is A in the ABO blood type system, and RH negative means that it is negative in the RH blood type. Because there are various human blood types, the main clinical application is the ABO blood type system and the RH blood type system. the ABO blood type system is relatively clear, and also know their own blood type, but the RH blood type is relatively unfamiliar to the majority of the people. the RH blood type is based on the red blood cell membrane contains a special D antigen to decide, if the red blood cell membrane contains the D antigen, even if the RH is positive; if it does not contain the D antigen is the RH negative. If the D antigen is present on the red blood cell membrane, it is considered RH positive; if it is not present, it is RH negative. RH-negative people are very rare in our country, and RH-negative people can only receive RH-negative blood. If RH-positive blood is transfused, serious hemolytic reactions can occur. Therefore, A type RH negative blood means that the ABO blood type is A blood and the RH blood type is negative.