Search results
Results From The WOW.Com Content Network
Blood compatibility testing is routinely performed before a blood transfusion.The full compatibility testing process involves ABO and RhD (Rh factor) typing; screening for antibodies against other blood group systems; and crossmatching, which involves testing the recipient's blood plasma against the donor's red blood cells as a final check for incompatibility.
It is estimated that less than 1ml of fetal blood is lost to the maternal circulation during normal labour in around 96% of normal deliveries. [1] [2] The loss of this small amount of blood may however be a sensitising event and stimulate antibody production to the foetal red blood cells, an example of which is Rhesus disease of the newborn.
Hemolytic disease of the fetus and newborn is similar to a transfusion reaction in that the mother's antibodies cannot tolerate the fetus's antigens, which happens when the immune tolerance of pregnancy is impaired. In many instances the maternal immune system attacks the fetal blood cells, resulting in fetal anemia. HDN ranges from mild to severe.
Intraperitoneal transfusion—blood transfused into fetal abdomen; Intravascular transfusion—blood transfused into fetal umbilical vein—This is the method of choice since the late 1980s, and more effective than intraperitoneal transfusion. A sample of fetal blood can be taken from the umbilical vein prior to the transfusion.
The effect of pregnancy on platelet count is unclear, with some studies demonstrating a mild decline in platelet count and other studies that show no effect. [24] The white blood cell count increases with occasional appearance of myelocytes or metamyelocytes in the blood. [24] During labor, there is a rise in leukocyte count.
Newborn Screening Tests - Transfusion with donor blood during pregnancy or shortly after birth can affect the results of the Newborn Screening Tests. It is recommended to wait and retest 10–12 months after the last transfusion. In some cases, DNA testing from saliva can be used to rule out certain conditions. [citation needed]
The final factor is related to the effects of pH on maternal and fetal hemoglobin. As the maternal blood acquires more carbon dioxide, it becomes more acidic and this favors the release of oxygen by the maternal hemoglobin. At the same time, the decrease in carbon dioxide in fetal blood makes it more alkaline and favors the uptake of oxygen.
The indirect Coombs test is used in prenatal testing of pregnant women and in testing prior to a blood transfusion. The test detects antibodies against foreign red blood cells. In this case, serum is extracted from a blood sample taken from the patient. The serum is incubated with foreign red blood cells of known antigenicity. Finally, anti ...