What does “Rh blood type positive” mean?

The Rh blood group system refers to the so-called “panda blood”—an extremely rare and uncommon blood type. Clinically, its significance ranks second only to the ABO blood group system. Generally, most people are familiar only with the four major ABO blood types—A, B, O, and AB—while few understand the Rh blood group system. In China, approximately 99.7% of the population has Rh-positive blood, whereas only 0.3% have Rh-negative blood. So, what exactly does “Rh-positive” mean? The following section provides a detailed explanation.

What does “Rh-positive” mean?

Rh-positive is one of the blood types within the Rh blood group system. Among the major human blood group systems, the two most clinically relevant are the ABO and Rh systems. The Rh factor refers specifically to the D antigen present on the surface of red blood cells. Individuals whose red blood cells express the D antigen are classified as Rh-positive; those lacking it are Rh-negative. According to available data, Rh-positive blood accounts for about 99.7% of the Han Chinese population and most other ethnic groups in China, while certain minority groups show a slightly lower prevalence—approximately 90%. Only 0.3% of the population is Rh-negative.

Additional Information: Pregnancy Considerations for Rh-Negative Women

1. Prenatal Immunohematologic Testing

For Rh-negative women experiencing their first pregnancy, prenatal immunohematologic testing should begin at gestational week 20 (i.e., five months). Antibody screening should then be repeated at weeks 28–32 and again at weeks 36–38. A follow-up antibody test is recommended approximately six months postpartum. Antibody formation during the first pregnancy is exceedingly rare; however, administration of anti-D immunoglobulin within 72 hours after delivery is advised. For optimal protection, anti-D immunoglobulin should also be administered between weeks 26–28 of gestation, followed by another dose within 72 hours postpartum—this regimen significantly enhances safety and efficacy.

2. Antibody Screening

Women with prior history of miscarriage or childbirth should commence Rh antibody screening at week 16 of gestation. Thereafter, monthly antibody testing is recommended until delivery, followed by a repeat antibody test approximately six months postpartum. If no anti-D antibodies are detected throughout pregnancy, anti-D immunoglobulin should be administered between weeks 26–28, and a second dose given within 72 hours postpartum.

The above outlines the meaning of “Rh-positive.” We hope this information proves helpful to you.