Hemolysis Patterns
Blood agar is a differential medium. It is NOT a selective medium! Blood agar allows distinction among bacteria based on their ability to lyse red blood cells The three types of hemolysis are:
Beta hemolysis, which is the complete lysis of red blood cells and hemoglobin. This results in complete clearing of the blood around the colonies.
Alpha hemolysis refers to the partial lysis of red blood cells and hemoglobin. This results in a greenish-grey discoloration of the blood around the colonies.
No hemolysis, sometimes called gamma hemolysis results in no change in the medium.