A positive Direct Antiglobulin Test (DAT or Direct Coombs Test) in a newborn indicates that the baby's red blood cells are coated with maternal IgG antibodies that have crossed the placenta. This is the key laboratory finding in Hemolytic Disease of the Fetus and Newborn (HDFN). The most common cause is Rh incompatibility (mother Rh-negative, baby Rh-positive with anti-D coating). However, ABO incompatibility (most often mother type O, baby type A or B) is actually a more frequent cause of a positive DAT, though the disease is usually milder. The maternal antibodies bound to the fetal red cells mark them for destruction by macrophages in the baby's spleen, leading to hemolytic anemia and jaundice after birth. A positive DAT, along with blood typing of mother and baby, helps confirm the diagnosis of HDFN and guides management, which may include phototherapy, intravenous immunoglobulin (IVIG), or exchange transfusion to prevent kernicterus.

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Zambia

• Joseph Soko – 101 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies