Finding The Blood Group Of Subject
The purpose of this lab is to perform blood typing of a given subject in order to know about his/ her blood group.Theory:
When blood from two individuals is mixed, sometimes clumping (agglutination) of RBCs occurs. This clumping is because of the immunological reactions.But, why clumping occurs in some cases and not in other cases remained a mystery until the discovery of blood groups by the Austrian Scientist Karl Landsteiner, in 1901. Determination of ABO blood groups depends upon the immunological reaction between antigen and antibody.Landsteiner found two antigens on the surface of RBCs and named them as A antigen and B antigen. These antigens are also called agglutinogens because of their capacity to cause agglutination of RBCs. He noticed the corresponding antibodies or agglutinins in the plasma and named them anti-A or α-antibody and anti-B orβ-antibody. However, a particular agglutinogen and the corresponding agglutinin cannot be present together. If present, it causes clumping of the blood.
Based on the presence or absence of antigen A and antigen B, blood is divided into four groups:
- ‘A’ group
- ‘B’ group
- ‘AB’ group
- ‘O’ group.
Rh FACTOR
Rh factor is an antigen present in RBC. This antigen was discovered by Landsteiner and Wiener. It was first discovered in Rhesus monkey and hence the name ‘Rh factor’. There are many Rh antigens but only the D antigen is more antigenic in human The persons having D antigen are called ‘Rh positive’and those without D antigen are called ‘Rh negative’.Requirements:
Subject, lancet, Slides, antiseras A.B.D cotton Alcohol.Procedure:
- Wash your hands properly with soap and allow it to dry.
- Sterilize your finger with cotton soaked in alcohol, and allow it to dry.
- Take a sterilized lancet and prick your finger collect a big drop of blood.
- Collect three big drops of blood on glass slide and mark them as A,B, and D.
- Add antisera A to drop A antisera B to drop B and antisera D to drop D.
- Mix it with glss slide and wait for fifteen minutes.
- After 15 min observe it if agglutination occur at drop A it will be blood group A.
- If agglutination occur at drop B it will be blood group B.
- If agglutination occur at drop A and B it will be blood group AB.
- If no agglutination occur it will be blood group O.
- If agglutination occur at drop D it will be blood group Rh positive and if no agglutination at drop D it will Rh negative.
Precautions:
- Lancet should be sterilized
- Carefully prick your finger
- Clean the laboratory after performing pratical procedure.
