B Rh positive, means that when checking the blood type, two blood grouping systems, ABO blood grouping system and Rh blood grouping system, are performed, in which the blood type is B blood and Rh positive blood, respectively. Blood type is usually judged according to the type of specific antigen present on the red blood cell membrane, and the two common ones are ABO blood group system and Rh blood group system. 1. ABO blood group system: According to the red blood cell membrane, antigen A and antigen B are alone, at the same time or not exist, can be divided into ABO blood type A, B, AB, O four types. 2. Rh blood group system: Rh blood group system, i.e. rhesus monkey blood group system, according to the presence or absence of D antigen on the red blood cell membrane, Rh blood group is divided into Rh-positive (presence of D antigen), Rh-negative (lack of D antigen). Rh-positive blood is common, while Rh-negative blood accounts for a small percentage of the population and is often referred to as “panda blood”. Both blood systems are tested when donating or transfusing blood.