Rh, ABO, Duffy, Kell, Kidd, MN
Rh, ABO, Duffy, Kell, Kidd, MN and *Platelet DNA Analysis *(Neonatal Alloimmune Thrombocytopenia Purpura)
Hemolytic disease of the fetus (unborn baby) and newborn occurs when the maternal immune system is sensitized to the baby's red blood cells. The surfaces of the red blood cells are covered with antigens, categorized as Rh, Kell, ABO, Duffy, Kidd, platelet, and MN antigens. When the fetus's antigens are different from those of the mother, the mother's immune system recognizes the baby's red blood cells as foreign and becomes sensitized to them. In a subsequent pregnancy, there is risk for hemolytic disease. If the fetus carries antigens different from the mother's, the mother's immune system responds by destroying the baby's red blood cells, a process known as hemolysis. This results in anemia, and if left untreated, death.
Who Should Be Tested?
Pregnant sensitized women may elect DNA analysis of amniocytes (baby's cells) to determine the fetal Rh, Kell, ABO, Duffy, Kidd, platelet, or MN type. DNA analysis can determine what antigens compose the fetus's red blood cells. Knowledge of the fetal antigen type will assist the physician in obstetric management. A negative test result, meaning that the fetus's cells are not in conflict with the mother's cells, allows discontinuation of serial amniocentesis and fetal blood sampling.
How Is Testing Performed?
Amniotic fluid cells are retrieved through a procedure known as amniocentesis. Amniocentesis involves removal of a small amount of the amniotic fluid that surrounds the baby using a fine needle inserted through the mother's abdomen. Fetal cells (amniocytes) float within the amniotic fluid. Once the amniocytes are retrieved, PCR (polymerase chain reaction) analysis is performed on the baby's DNA to determine what antigens compose the baby's red blood cells. To analyze for Kell, Duffy, Kidd, MN antigens and platelets, parents' bloods must also be tested.
How Soon Can This Test Be Completed?
The analysis is completed in about 1 week.
Information provided on this site is for information purposes ONLY. This should not be used as a substitute for professional medical advice, treatment or diagnosis.