1. Blood grouping

2. Experiments with blood transfusions, the transfer of blood or blood components into a person's blood stream, have been carried out for hundreds of years.
Many patients have died and it was not until 1901, when the Austrian Karl Landsteiner discovered human blood groups, that blood transfusions became safer.

3. Mixing blood from two individuals can lead to blood clumping or agglutination.
The clumped red cells can crack and cause toxic reactions.
This can have fatal consequences.
Karl Landsteiner discovered that blood clumping was an immunological reaction which occurs when the receiver of a blood transfusion has antibodies against the donor blood cells.

4. Karl Landsteiner's work made it possible to determine blood groups and thus paved the way for blood transfusions to be carried out safely.
For this discovery he was awarded the Nobel Prize in Physiology or Medicine in 1930.

5. What are the different blood groups?
The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies.
The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma.
Individuals have different types and combinations of these molecules.
The blood group you belong to depends on what you have inherited from your parents.

6. Not all blood groups are compatible with each other.
There are more than 20 genetically determined blood group systems known today, but the AB0 and Rh systems are the most important ones used for blood transfusions.
Not all blood groups are compatible with each other.
Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.
Nobel Laureate Karl Landsteiner was involved in the discovery of both the AB0 and Rh blood groups.

7. AB0 blood grouping system
According to the AB0 blood group system there are four different kinds of blood groups: A, B, AB or 0

8. Blood group A
If you belong to the blood group A, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma.

9. Blood group B
If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma.

10. Blood group AB
If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma.

11. Blood group 0
If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma.

12. Rh factor blood grouping system
Many people also have a so called Rh factor on the red blood cell's surface.
This is also an antigen and those who have it are called Rh+.
Those who haven't are called Rh-.
A person with Rh- blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance).

13. Rh factor blood grouping system
But a person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies.
A person with Rh+ blood can receive blood from a person with Rh- blood without any problems.

15. Blood group notation
According to above blood grouping systems, you can belong to either of following 8 blood groups:
Rh+B (B+) Rh-B (B-)
Rh+AB (AB+) Rh-AB (AB-)
Rh+0 (O+) Rh-0 (O-)
Rh+A (A+) Rh-A (A-)
Do you know which blood group you belong to?

16. Blood typing – how do you find out to which blood group someone belongs?
1. You mix the blood with three different reagents including either of the three different antibodies, A, B or Rh antibodies.

17. Then you take a look at what has happened
Then you take a look at what has happened. In which mixtures has agglutination occurred? The agglutination indicates that the blood has reacted with a certain antibody and therefore is not compatible with blood containing that kind of antibody. If the blood does not agglutinate, it indicates that the blood does not have the antigens binding the special antibody in the reagent.

18. 3. If you know which antigens are in the person's blood, it's easy to figure out which blood group he or she belongs to!

19. Type of antibody
Blood group antibodies are mainly IgM, e.g. anti-A and anti-B, and IgG, e.g. immune anti-Rh antibodies.
IgM antibodies are large molecules easily able to bind to antigens (10 binding sites) and link red cells together, causing their agglutination in a saline medium. They are also able to activate and bind complement.
IgG antibodies are much smaller with only two antigen binding sites, resulting in red cells being sensitized but not agglutinated in saline. Albumin, antiglobulin reagent, or proteolytic enzymes are used to agglutinate IgG sensitized red cells in laboratory tests

20. Ionic strength of medium
The rate at which antigen-antibody reactions occur is increased when the ionic strength of a medium is reduced, e.g. when red cells are suspended in low ionic strength saline (LISS).
Temperature: Most immune IgG antibodies react best at warm temperatures while IgM antibodies react best at room temperature and colder temperatures.

21. pH
A pH of between 6.5–7.5 is best suited for blood group antigen-antibody reactions.
Ratio of antibody to antigen: There must be an optimum rate of antibody to antigen sites for agglutination of red cells to occur. The red cell suspension used in agglutination tests must not be too strong.

22. RHESUS GROUPING To perform Rhesus grouping the following are required:
● Blood sample
● Anti-D serum
● Controls

23. Secretors
Up to 80% or more of people inherit the secretor gene Se and secrete water soluble H, A, and B antigens in their saliva, plasma, and other body fluids in addition to expressing the antigens on their red cells. But not important in routine blood transfusion practice.

24. In leukaemia and some other diseases, red cell antigens can disappear or become weaker while in other malignant diseases e.g. gastrointestinal cancer, a B like antigen substance is occasionally produced in group A persons

25. What happens when blood clumps or agglutinates?
For a blood transfusion to be successful, AB0 and Rh blood groups must be compatible between the donor blood and the patient blood.
If they are not, the red blood cells from the donated blood will clump or agglutinate.
The agglutinated red cells can clog blood vessels and stop the circulation of the blood to various parts of the body.
The agglutinated red blood cells also crack and its contents leak out in the body.
The red blood cells contain hemoglobin which becomes toxic when outside the cell.
This can have fatal consequences for the patient.

26. a B blood person receives blood from an A blood person.
The red blood cells will be linked together, like bunches of grapes, by the antibodies.
As mentioned earlier, this clumping could lead to death.

27. Blood transfusions – who can receive blood from whom?
Of course you can always give A blood to persons with blood group A, B blood to a person with blood group B and so on.
But in some cases you can receive blood with another type of blood group, or donate blood to a person with another kind of blood group.

28. Cont.
The transfusion will work if a person who is going to receive blood has a blood group that doesn't have any antibodies against the donor blood's antigens.
But if a person who is going to receive blood has antibodies matching the donor blood's antigens, the red blood cells in the donated blood will clump.

29. Cont.
People with blood group 0 Rh - are called "universal donors" and people with blood group AB Rh+ are called "universal receivers."

31. Compatibility testing
The purpose of compatibility testing (crossmatching) is to prevent a transfusing reaction by ensuring:
● The ABO group of the blood to be transfused is compatible with the patient’s ABO group.
● There are no detectable irregular antibodies in the patient’s serum that will react with the donor’s red cells, causing their destruction or reducing their normal survival.

32. Action to take when a transfusion reactionoccurs
When a reaction occurs the transfusion must be stopped and the attending medical officer notified immediately and also laboratory personnel. There should be a standardized procedure for investigating a transfusion reaction and recording clinical and laboratory findings. The laboratory investigations

33. Difficulties in ABO grouping
Discrepancies in ABO grouping can be caused by
faulty technique, deterioration of reagents (antisera or test cells), or by rouleaux or autoagglutinins.

34. Patient’s blood sample
For blood grouping and compatibility testing, collect blood into EDTA anticoagulant (see subunit 8.3) and 5–7 ml into a dry clean glass tube (not plastic). Label the containers clearly with the patient’s name, hospital number, ward, and date

35. . The EDTA blood is used to obtain red cells for cell grouping and to measure the patient’s haemoglobin or packed cell volume.
Serum from the clotted blood sample is used for serum grouping and compatibility testing

36. When blood is collected in advance, the serum for compatibility test must not be more than 48 hours old.
Serum used for compatibility testing should be kept by the laboratory for 3 days following a transfusion in case it is needed for re-testing in the unlikely event of a transfusion reaction.

37. When blood is held for a patient who has been transfused, it must be re-crossmatched when more than 48 hours have passed since the first transfusion.

38. Fresh blood, not more than 2–3 days old, is required when transfusing infants and patients with conditions that require regular transfusion, e.g. thalassaemia patients to ensure the transfused red cells survive as long as possible in the patient. In district hospitals, in the absence of specific blood components, fresh blood is also used to treat patients with bleeding disorders.

39. A compatibility test is a final check on the compatibility of blood for a patient, particularly ABO compatibility.
Compatibility testing is essential when prior antibody screening is not performed.
A simple to perform single tube technique comprising the following three stages is recommended.

40. Detection of ABO incompatibility in saline at room temperature: Donor’s cells are mixed with patient’s serum at room temperature, centrifuged and examined visually for agglutination. When there is no agglutination or haemolysis, proceed to next stage.

41. Detection of antibodies agglutinating at 37 C in saline
Detection of antibodies agglutinating at 37 C in saline. The tube is incubated at 37 C for 20 minutes, recentrifuged and examined for agglutination. When there is no agglutination or haemolysis, proceed to the third stage.

42. Detection of immune IgG antibodies that have sensitized donor’s cells and are only agglutinated by using antiglobulin (AHG) reagent:* An indirect antiglobulin test (IAT) is performed in which red cells after being incubated in patient’s serum are tested after washing for bound antibody.

43. Preparation of concentrated (packed) red cells
In most blood transfusion centres, blood is collected into blood bags with an attached empty bag into which plasma can be transferred in a closed system after centrifuging the blood in a refrigerated centrifuge.

44. When a district hospital is not supplied with red cell concentrates from a blood transfusion centre, concentrated red cells can be prepared after storing blood packs in an upright position in the blood bank and the cells have sedimented (after about 8 hours).

45. When a district hospital is not supplied with red cell concentrates from a blood transfusion centre, concentrated red cells can be prepared after storing blood packs in an upright position in the blood bank and the cells have sedimented (after about 8 hours).

46. Transfusion reaction
A severely anaemic patient may react adversely to a blood transfusion when blood is transfused too quickly or too much whole blood is transfused causing circulatory overload.
Most reactions to transfused blood are minor non-haemolytic febrile reactions causing shivering and a slight rise of temperature.

47. Malaria parasites will often cause a temperature rise and also antibodies to leukocytes or platelets.
Occasionally allergic anaphylactic reactions occur with urticaria (skin rash) and sometimes bronchial spasm due to hypersensitivity to plasma protein antigens. Allergic reactions are less common when using concentrated red cells.

48. Haemolytic transfusion reactions
The most serious often fatal transfusion reactions are caused by:
● Transfusing ABO incompatible blood due to patient misidentification, incorrect labelling of specimens, or serological errors made in the laboratory.

49. Transfusing infected blood, commonly caused by inadequate cleansing of the venepuncture site when collecting blood from a donor.
Blood can also become infected when air is allowed to enter a blood bag, e.g. when the same unit of blood is used to transfuse several children on successive days.

50. ● Transfusing blood which has expired, has been haemolyzed by being stored next to the freezing compartment of a refrigerator, or has been stored at temperatures higher than 8 C.

51. Action to take when a transfusion reaction occurs
Collecting the blood pack and checking that the patient has received the correct blood and that there has been no error due to incorrect labelling or misreading of names or hospital numbers.

52. Collecting the blood pack and checking that the patient has received the correct blood and that there has been no error due to incorrect labelling or misreading of names or hospital numbers.

53. Examining a stained blood film for spherocytosis and red cell fragmentation.
– Centrifuging the EDTA blood and examining the plasma for haemolysis.
– Testing the urine for haemoglobin
and examining it microscopically for cellular casts.
– Checking for DIC by performing a platelet count and when possible an FDP test

54. Testing pre- and post-transfusion samples and the donor blood for ABO incompatibility.
Examining the blood for bacterial contamination.