For cultivation of fastidious organisms and studying haemolytic reactions.
This medium is both differential and enriched medium and used for the isolation, cultivation and detection of hemolytic activity of fastidious microorganisms like Streptococci, and Pneumococci. The Blood Agar plate medium contains highly nutritious extract and the 5 % blood supplement that provides additional use in isolation, cultivation, and determination of hemolytic reactions of fastidious pathogenic microorganisms. Hemolytic patterns may vary with the source of animal blood or type of base medium used. In sheep blood, nucleotidase destroys V factors preventing the growth of Hemophilus species on sheep blood agar unless other microorganisms, such as Staphylococci, provide the V factors. Small amounts of reducing sugars inhibit the expression of β-hemolytic, and β-hemolytic Streptococci may develop a green zone or ring of hemolysis.