Antigens A and B are the best known, but not the only ones that exist in human blood is another, called Rh factor, which is found in red blood cells more than 85% of the population worldwide. This component is important when a woman with Rh negative (no Rh antigen) conceives a child of a man who is Rh positive (Rh antigen in their blood), because this fact may pose a hazard to the fetus or the newborn. How the mother may have acquired these antibodies destructive? It may have been by a Rh-positive blood transfusion or a previous pregnancy if the fetus’s blood mixed with it at the time of delivery or abortion. The first pregnancy of this kind involves little risk because the formation of antibodies takes time, but once the mother’s blood has been sensitized, Rh incompatibility can be a serious problem in subsequent pregnancies. To avoid this danger, physicians administered to Rh negative mothers after each pregnancy, a desensitizing recently discovered, so that your blood will not form antibodies that destroy the Rh positive red blood cells. Another modern technique is to fully replace the newborns blood through a transfusion.
What is a blood count?
A blood count is to determine the number of erythrocytes, leukocytes, platelets and hemoglobin content of blood studying a small sample of it. The number or percentage obtained is compared with normal values to see if there is an excess or deficiency of any of them. In a more detailed breakdown of biometrics the relative amount of each of the different types of white blood cells. Abnormalities in their number may indicate an allergic reaction, infection or blood disease. To make a biometrics begins to dilute the blood sample in a solution of distilled water and salts to disperse the blood cells. It takes a certain volume of the diluted sample and spread evenly on a slide grid, called a counting chamber, which takes up a cover slip. Then he takes the microscope and hematologist the number of cells of each type in a number of grids. Today, that work can do the scanning electron microscopes.