Blood Agar Base pH 7.4, to which blood may be added to make it more nutritious, is used for the isolation and cultivation of fastidious microorganisms like Neisseria and Streptococci. Its low pH (6.8) stabilizes the red blood corpuscles and favors the formation of a clear hemolysis zone. If the medium is to be used without blood supplementation, pH must be adjusted to 7.2-7.4. Beef Extract and Tryptose provide nutrients like amino acids, peptides, carbohydrates, vitamins, and minerals. Sodium Chloride maintains the osmotic balance and Agar serves as gelifying agent.
