Step-by-Step Guide to ABO Blood Grouping Technique

Introduction: What is Blood grouping?

Blood grouping is a laboratory procedure for categorizing blood into different types with the presence or absence of certain molecules called antigens on red blood cells. A person’s blood type depends on the genes they inherited from their parents.

The ABO blood group system is the most important blood type system (or blood group system) in human blood transfusion. ABO blood types are also present in some other animals for example rodents and apes such as chimpanzees, bonobos and gorillas

History

Karl Landsteiner discovered the ABO Blood Group System in 1901.
Adriano Sturli and Alfred von Decastello who were working under Landsteiner discovered type AB a year later in 1902
Landsteiner was awarded the 1930 Nobel Prize in Physiology or Medicine for his work.
Janský is credited with the first classification of blood into the four types (A, B, AB, O) in 1907, which remains in use today.
Reuben Ottenberg successfully transfused blood between two people at Mount Sinai Hospital in New York. He was the first person to record pre-transfusion testing for blood compatibility in a clinical setting. Later in 1954 he was the first to be awarded with Karl Landsteiner Award

Landsteiner Rule

If an antigen is present on a patients red blood cells (RBCs) the corresponding antibody will NOT be present in the patients plasma, under ‘normal conditions

ABO Blood grouping basics

Determination of ABO blood groups depends upon the immunological reaction between antigen and antibody. Antigens are also called agglutinogens because of their capacity to cause agglutination of RBCs.

The classification of blood groups based on the presence or absence of antigens A and B on the surface of red blood cells is called ABO blood grouping.

Based on the presence or absence of antigen A and antigen B, blood is divided into four main categories:

‘A, B, AB and ‘O’ group.

Blood having antigen A belongs to ‘A’ group. This blood has β-antibody in the serum.
Blood with antigen B and α-antibody belongs to ‘B’ group.
If both the antigens are present, blood group is called ‘AB’ group and serum of this group does not contain any antibody.
If both antigens are absent, the blood group is called ‘O’ group and both α and β antibodies are present in the serum.

Principle of Blood Grouping

Blood grouping is done on the basis of agglutination. Agglutination means the collection of separate particles like RBCs into clumps or masses. Agglutination happens if an antigen is mixed with its corresponding antibody which is called isoagglutinin, i.e. occurs when A antigen is mixed with anti-A or when B antigen is mixed with anti-B.

Significance of ABO grouping system

During blood transfusion, only compatible blood must be used.
The one who gives blood is called the donor and the one who receives the blood is called recipient.
While transfusing the blood, antigen of the donor and the antibody of the recipient are considered.
The antibody of the donor and antigen of the recipient are ignored mostly. Thus, RBC of ‘O’ group has no antigen and so agglutination does not occur with any other group of blood. So, ‘O’ group blood can be given to any blood group persons and the people with this blood group are called „universal donors

In mismatched transfusion, the transfusion reactions occur between donor’s RBC and recipient’s plasma. So, if the donor’s plasma contains agglutinins against recipient’s RBC, agglutination does not occur because these antibodies are diluted in the recipient’s blood

The Rh blood grouping system

The Rh blood group system is one of thirty- five current human blood group systems.
It is the most important blood group system after ABO.
Rh blood group system consists of 50 defined blood-group antigens, among them there are six common types of Rh antigens.
Each of which is called an Rh factor. These types are designated C,D, E, c, d, and e.

The type D antigen is widely prevalent in the population and considerably more antigenic than the other Rh antigens.
Anyone who has this type of antigen is said to be Rh positive, whereas a person who does not have type D antigen is said to be Rh negative.

Procedure for ABO Blood grouping:

Various techniques are available for ABO grouping in the laboratory. These are:

Slide technique
Tube technique
Microplate technique
Gel card technique

blood grouping using Slide technique

This can be performed in emergency or outdoor camps but must not be performed as a routine test

Material required

Glass slides/white tile
Monoclonal Anti-sera A Anti-sera B and anti-D
Glass rod for mixing
Marker pen

Sample:

Blood collected in a plain vial. Sample must be tested within 48hours. It should be kept in the refrigerator till processed. There should be no evidence of hemolysis in the sample.

Procedure

Clean the slides and mark three points as A, B and D.
Clean one of the fingers by rubbing with cotton soaked in rectified spirit.
When the finger dries, prick the tip of the finger with the sterile needle so that blood comes out.
Put one drop of blood each near the points A, B and D.
Put one drop of anti-serum A, B and D on the blood drops near the points A, B and D respectively.
Mix the liquids at each of the three points with the wooden ends of three separate clean matchsticks.

Observation

Theoretically, we know that

If blood near point A agglutinates, then the blood group is ‘A’.
If blood near point B agglutinates, then the blood group is ‘B’.
If blood near both the points A and B agglutinate, then the blood group is ‘AB’.
If neither of blood near point A or B agglutinates, then the blood group is ‘O’.
If blood near point D agglutinates, then the blood group is ‘Rh positive’, else it is “Rh negative’.
In this procedure, it was found that blood near points ‘B’ and ‘D’ agglutinate. So the blood used here is B positive.

Advantages of slide method

Can be used in emergency and blood camps for preliminary grouping.
Easy to perform
Quick

Disadvantages of slide method

Not reliable for weak reactions as negative results cannot be checked microscopically.
Serum testing cannot be performed.
The test mixture tends to dry fast.
Drying causes aggregation of cells which can be interpreted as agglutination.
Less sensitive than tube technique.

Since the blood used in the present experiment agglutinated with anti-B and anti-D serum, therefore it can be concluded that it belongs to blood group B positive.

Other blood groups

An individual can be AB Rh D positive, and at the same time M and N positive (MNS system), K positive (Kell system), and Lea or Leb positive (Lewis system). Many of the blood group systems were named after the patients in whom the corresponding antibodies were initially encountered.

Other blood groups include