wait and retest 10–12 months after last transfusion. In some cases, DNA testing from saliva can be used to rule out certain conditions. Treatment The antibodies in ABO HDN cause anemia due to destruction of fetal red blood cells and jaundice due to the rise in blood levels of bilirubin a by-product of hemoglobin break down. If the anemia is severe, it can be treated with a blood transfusion, however this is rarely needed. On the other hand, neonates have underdeveloped livers that are unable to process large amounts of bilirubin and a poorly developed blood–brain barrier that is unable to block bilirubin from entering the brain. This can result in kernicterus if left unchecked. If the bilirubin level is sufficiently high as to cause worry, it can be lowered via phototherapy in the first instance or an exchange transfusion if severely elevated. Phototherapy - Phototherapy is used for cord bilirubin of 3 or higher. Some doctors use it at lower levels while awaiting lab results. IVIG - Intravenous Immunoglobulin therapy (IVIG) has been used to successfully treat many cases of HDN. It has been used not only on anti-D, but on anti-E as well. IVIG can be used to reduce the need for exchange transfusion and to shorten the length of phototherapy. The AAP recommends "In isoimmune hemolytic disease, administration of intravenous γ-globulin (0.5-1 g/kg over 2 hours) is recommended if the TSB is rising despite intensive phototherapy or the TSB level is within 2 to 3 mg/dL (34-51 μmol/L) of the exchange level . If necessary, this dose can be repeated in 12 hours (evidence quality B: benefits exceed harms). Intravenous γ-globulin has been shown to reduce the need for exchange transfusions in Rh and ABO hemolytic disease." Exchange transfusion - Exchange transfusion is used when bilirubin reaches either the high or medium risk lines on the normogram provided by the American Academy of Pediatrics (Figure 4). Cord bilirubin >4 is also indicative of the need for exchange transfusion. See also Coombs test Hemolytic anemia Hematology References External links Haemorrhagic and haematological disorders of fetus and newborn Disorders originating in the perinatal period Transfusion medicine Neonatology Acquired hemolytic anemia