State the law of mass action
“Free reactants are in equilibrium with bound reactants “
Illustrate the law of Mass Action
Antigen + Antibody ➡️ AgAb
⬅️
This depends on the strength of binding of antigen and antibody
Equilibrium
What are the 2 types of serologic tests
1) forward / direct serological test
2) backward serological test
Detect unknown antigen using unknown antibody
Forward / direct serological test
Detect known antigen using known antibody
Backward serological test
Example of forward serological test
Forward / red cell blood typing
Reaction in Forward / red cell blood typing
Blue = anti A Yellow = anti B
Example of backward serological test
Serum blood typing