Even non-medical experts have heard of blood groups and various combinations, a subject that has been studied for many years, since 1900 when a researcher was able to show the existence in human red blood cells of two different antigens (called agglutinogens). He decided to assign them the letters A and B. All this happened while he was studying the agglutination that occurs when you put the red blood cells of one subject in a second subject.
Blood groups: combinations
Observing the presence orabsence of antigens in the blood of a person can be assigned to one or the other blood group. In total, four were identified system groups A, B, 0 and precisely the groups 0, A, B and AB.
Let's start with the first, group 0, with antigen-free red blood cells. Then there is group A with Red blood cells containing antigen A, group B goes without saying that it has red blood cells containing antigen B, finally there is group AB with red blood cells containing both antigen A and antigen B.
Another element to look out for are agglutinins, found in the serum. There are anti A and anti B agglutinins and agglutinates respectively erythrocytes of group A or group B and erythrocytes of the AB group. Let's see how they behave in each group. In B there are anti A agglutinins in the serum and in group A there are anti B agglutinins. In group 0 there are both agglutinins, A and B, totally absent in the serum of subjects of group AB.
When evaluating the combinations of blood groups what is important to check is that the donor's red blood cells are not agglutinated by the recipient's red blood cells. On the other hand, the agglutination of the recipient's red blood cells by the donor's agglutinins is more frequent.
Blood groups: how to recognize them
There are various techniques to determine which blood group you belong to, such as the slide method or the tube method.
To identify groups A, B and AB, human anti-A tests and anti-B test sera are sufficient and colors are usually used: the anti A test is in blue and hosts alpha agglutinins while the anti B texts it is yellow and has beta agglutinins. Once the slide is taken, a drop of blood drawn from the fingertip with a small prick and then add 2 or 3 grams of drops of test serum.
It only takes a few minutes and then you can get the result. If the blood placed on the slide is not hemolyzed, the individual belongs to group 0, if instead theagglutination in the serum test anti A we are in the case of group A, similarly if it occurs in the serum B test, we are in group B. It remains only the case where the agglutination occurred in both slides, it is the case of group AB.
Blood groups and parameters
After understanding the mechanism of groups, let's find out some of the fundamental parameters concerning blood. Very often thecomplete blood count, it is used to know the number of red blood cells, white blood cells and hemoglobin in the blood.
If we look at hemoglobin, for example, we must refer to values between 13 and 20 grams in men, between 11 and 18 grams in women. In case of anemia, parasitic infections, infectious diseases and haemolytic anemia much lower values are obtained, if instead you have cyanosis or suffer from severe diarrhea, the values are much higher. Also of interest are erythrocytes which are higher than normal in severe diarrhea, in some chronic heart disease, in some acute poisonings and in pulmonary fibrosis. On the contrary, the values are low in all anemias, in leukemias and after haemorrhages.
THE leukocytes they are normal if they range from 6,000 to 8,000 per mm3, if they are greater, the causes can be many, This happens for example during digestion, after cold baths and during pregnancy, but it can also be a pathological signal related to infectious diseases, malignant tumors, intoxication by exogenous poisons. What if we have too few leukocytes? It can be due to infectious diseases, pernicious anemia, Banti's disease or sulfonamide, thiuracil, antifungal drugs.
The globular value is the ratio of the percentage of hemoglobin and the number of erythrocytes. Taking into account that the normal values are 0.90 - 1.10, hypochromic anemias are found below, while hyperchromic anemias are above.
It is also possible to count the platelets which are normally 300,000-400,000 per mm3. They are important elements for protecting the vessel walls when the endothelium suffers injuries but we also find them around wounds, traumatized surfaces or foreign bodies. When the platelets drop below 60,000, one can clinically speak of a bleeding state.
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