Rhpositive

Rh positive refers to individuals whose red blood cells express the D antigen of the Rh blood group system. The presence of the D antigen on erythrocytes classifies blood as Rh-positive; absence classifies as Rh-negative. The Rh system includes several antigens, with D being the most clinically significant. People inherit their Rh status from their parents, and in many populations about 85% are Rh-positive, though the exact proportion varies by ethnicity and region. Some individuals have weak D variants, which can affect testing and transfusion decisions in certain settings.

Rh testing is routinely performed in blood typing and transfusion medicine. Before a blood transfusion, donor and recipient are checked for ABO and Rh compatibility to prevent immune reactions. If an Rh-negative person is exposed to Rh-positive blood, they can develop anti-D antibodies, a process known as sensitization. This is especially relevant in pregnancy.

Rh incompatibility between an Rh-negative pregnant person and an Rh-positive fetus can lead to hemolytic disease of the fetus and newborn (HDFN) if not managed. Preventive treatment with Rh immune globulin (Rho(D) immune globulin) is commonly given during pregnancy and after delivery or potential fetal-metal blood mixing to prevent maternal sensitization.

Rh status is not a disease or condition but a key factor in transfusion and obstetric care. Understanding Rh positivity helps guide safe blood transfusions and helps manage pregnancy to reduce risks associated with Rh incompatibility.