For enrichment and isolation of fastidious microorganisms with or without blood. SOYA PEPTONE DIGEST AGAR is used for enrichment and isolation of fastidious microorganism with or without blood. This medium is highly nutritious versatile medium for the growth of wide variety of organisms like Haemophilus, Neisseria, Listeria and Brucella etc. This medium is also used for determination of antimicrobial agent in food and other products. Since this medium contains no added carbohydrates, it can also be used as blood agar base as 7% of the sterile blood is added to sterile molten medium. This blood added medium provided a well defined haemolysis zone. This is recommended as a reference medium when testing selective media, to measure the degree of inhibition. Since the medium does not contain the X and V growth factors, it can conveniently be used in determining the requirements for these growth factors by isolates of Haemophilus by the addition of X, V and XV Factor Strips to inoculated plates. The combination of Pancreatic digest of casein and Soya peptone in this renders the medium highly nutritious by supplying organic nitrogen, particularly amino acids and longer-chained peptides. The Sodium chloride maintains osmotic equilibrium. Agar is the solidifying agent.