Is blood type B- the same as B rhesus negative?
Yes, the B negative is the same as saying B Rhesus negative. And she’s right, it is very rare. Rh-negative blood is rare enough, and B is the second-rarest type after AB. The only negative blood type that is tested for is the Rhesus-factor. Blood testing kits tell you whether you are AB, A, B or O, and either Rh positive or negative. Negative just means you don’t have the Rhesus antigen on your blood cells.