also be run. Anti-Kell hemolytic disease of the newborn is most commonly caused by anti-K1 antibodies, the second most common form of severe HDN. Over half of the cases of anti-K1 related HDN are caused by multiple blood transfusions. Antibodies to the other Kell antigens are rare. Anti-Kell can cause severe anemia regardless of titer. It suppresses the bone marrow by inhibiting the erythroid progenitor cells. Anti-M also recommends antigen testing to rule out the presence of HDN as the direct coombs can come back negative in a severely affected infant. Kidd antigens are also present on the endothelial cells of the kidneys. One study states that it would be unwise to routinely dismiss anti-E as being of little clinical consequence. It also found that the most severe case of anti-E HDFN occurred with titers 1:2, concluding that titers are not reliable for the diagnosis of the anti-E type. Diagnosis The diagnosis of HDN is based on history and laboratory findings: Blood tests done on the newborn baby Biochemistry tests for jaundice including total and direct bilirubin levels. Complete blood count (CBC) which may show a decreased hemoglobin and hematocrit due to red blood cell destruction Reticulocyte count which will usually be increased as the bone marrow makes new red blood cells to replace the ones that are being destroyed, and a peripheral blood smear to look at cell morphology. In the presence of significant hemolysis the smear will show schistocytes (fragmented red blood cells), reticulocytosis, and in severe cases Erythroblasts (also known as nucleated red blood cells). Positive direct Coombs test (might be negative after fetal interuterine blood transfusion) Blood tests done on the mother Positive indirect Coombs test Blood tests done on the father (rarely needed) Erythrocyte antigen status Prevention In cases of Rho(D) incompatibility, Rho(D) immunoglobulin is given to prevent sensitization. However, there is no comparable immunotherapy available for other blood group incompatibilities. Early pregnancy IVIG – IVIG stands for Intravenous Immunoglobulin. It is used in cases of previous loss, high maternal titers, known aggressive antibodies, and in cases where religion prevents blood transfusion. IVIG can be more effective than IUT alone. Fetal mortality was reduced by 36% in the IVIG and IUT group than in the IUT alone group. IVIG and plasmapheresis together can reduce or eliminate the need for an IUT. Plasmapheresis – Plasmapheresis aims to decrease the maternal titer by direct plasma replacement and