Columbia Blood Agar Base is an enriched agar medium used for the cultivation of fastidious and non-fastidious microorganisms. The medium is usually prepared with horse, sheep, or rabbit blood to determine the hemolytic reactions of fastidious pathogenic microorganisms. Columbia Blood Agar Base can be prepared as Blood Agar or Chocolate Agar or used without blood as a general purpose medium. This medium contains a highly nutritious combination of peptones. The addition of starch enhances the recovery of Neisseria, and the hemolytic reaction of some streptococci.