What is the purpose of Direct Antiglobulin Test (DAT) in newborn blood bank testing?

From the Guidelines

The Direct Antiglobulin Test (DAT) should be performed on all newborns with a suspected risk of hemolytic disease, particularly those born to mothers with blood type O, Rh-negative status, or known antibodies, as it is crucial for early identification and management of potential hemolysis 1. When considering the importance of DAT in newborn testing, it is essential to understand its role in detecting antibodies attached to the newborn's red blood cells, which can cause hemolysis. A positive DAT indicates that maternal antibodies have bound to the baby's red cells, potentially causing anemia, jaundice, or more severe complications. The DAT is particularly relevant in the context of hyperbilirubinemia management, as outlined in the recent guidelines for phototherapy to prevent severe neonatal hyperbilirubinemia 1. Key points to consider in DAT blood bank newborn testing include:

• The test should be conducted on cord blood samples of infants born to mothers with blood type O, Rh-negative status, or those with known antibodies.
• A positive DAT result indicates the need for close monitoring of bilirubin levels and hemoglobin concentration.
• Treatment depends on the severity of the condition and may include phototherapy, intravenous immunoglobulin, or in severe cases, exchange transfusion.
• The DAT is an essential tool for early identification of at-risk newborns, allowing for prompt intervention to prevent kernicterus and other complications of severe hyperbilirubinemia. In clinical practice, the DAT result guides management decisions, including the need for intensive phototherapy, as recommended in the guidelines for newborns with hyperbilirubinemia 1. Therefore, the DAT should be performed promptly after birth in at-risk newborns to guide management decisions and prevent potential complications of hemolytic disease 1.

From the Research

DAT Blood Bank Newborn Testing

• DAT (Direct Antiglobulin Test) blood bank newborn testing is used to diagnose hemolytic disease of the newborn (HDN) caused by blood type incompatibility between the mother and the baby.
• The test detects the presence of antibodies or complement proteins attached to the baby's red blood cells, which can cause hemolysis (breakdown of red blood cells) 2, 3, 4, 5, 6.

Treatment of Hemolytic Disease of the Newborn

• Conventional treatments for HDN include phototherapy, exchange transfusion, and hydration 2, 3, 4, 5, 6.
• Intravenous immunoglobulin (IVIG) has been investigated as an alternative treatment to reduce the need for exchange transfusion 3, 4, 5, 6.
• Studies have shown that IVIG can decrease the need for exchange transfusion in some cases, but the evidence is limited and further research is needed to confirm its effectiveness 3, 4, 5, 6.

Effectiveness of IVIG in Reducing Exchange Transfusion

• A study published in 2002 found that IVIG reduced the need for exchange transfusion in newborns with isoimmune hemolytic jaundice 4.
• A 2018 Cochrane review found that IVIG decreased the use of exchange transfusion in newborns with alloimmune HDN, but the quality of evidence was low to very low 6.
• Another study published in 2006 found that IVIG was effective in reducing the need for exchange transfusion in newborns with Rh hemolytic disease, but not in those with ABO hemolytic disease 5.

Safety and Complications of IVIG

• IVIG is generally considered safe, but it can cause adverse effects such as apnea, and late anemia 3, 5.
• The risk of complications is lower with IVIG compared to exchange transfusion, which can cause serious adverse effects such as infection, bleeding, and death 3, 6.