Cord Blood Typing: ABO and Rh Blood Type Testing of Newborn Umbilical Cord Blood

What is this test? Cord blood typing is a laboratory test that identifies your baby's blood type, including the ABO group and Rh factor, using a small sample of blood taken from the umbilical cord after birth.

The ABO group test determines your baby's blood type using cord blood—the blood that remains in the umbilical cord and placenta after birth. This blood contains the same blood type information as the baby's bloodstream. The test identifies whether the baby's blood is type A, B, AB, or O, which refers to the presence or absence of specific antigens (A and B) on the surface of red blood cells.

How is the test performed? After your baby is delivered and the umbilical cord is clamped and cut, a healthcare provider collects a small blood sample from the cord vein. The sample is sent to a laboratory, where trained staff test it to determine the blood type. The procedure is quick and painless for both you and your baby.

After your baby is born, the healthcare provider clamps and cuts the umbilical cord as usual. Before or shortly after the placenta is delivered, a small sample of cord blood is collected from the clamped cord using a needle and syringe or by allowing blood to drip into a collection tube. This sample is then sent to the laboratory for analysis. The procedure does not harm the baby or the mother and uses blood that would normally be discarded.

Why is cord blood typing important? Knowing your baby's blood type helps doctors respond quickly if a blood transfusion is ever needed. It can also reveal an Rh incompatibility between you and your baby, which may require monitoring or follow-up care to protect your newborn's health.

Knowing your baby's blood type is important for several reasons. First, it provides baseline health information that may be needed throughout the child's life. Second, it helps healthcare providers identify any potential blood type incompatibility between mother and baby, which could cause jaundice in newborns. Third, cord blood contains valuable stem cells that can be collected and stored in cord blood banks for potential future medical use. Finally, the blood type information becomes part of the permanent medical record.

What do the results mean? The results show your baby's ABO blood group (A, B, AB, or O) and Rh factor (positive or negative). A clearly identified blood type simply documents your baby's blood characteristics. If the results suggest an unexpected type or a possible incompatibility with yours, your baby's healthcare provider will discuss any additional testing or treatment that may be needed.

Blood type is determined by genes inherited from parents. Type A blood has A antigens, type B has B antigens, type AB has both A and B antigens, and type O has neither. Each type can be Rh-positive or Rh-negative, though this specific test focuses on the ABO group. Your healthcare provider will explain your baby's specific blood type and whether any follow-up is needed. In most cases, the results are simply recorded for future reference.