Diagnostic Sensitivity Test Agar (D.S.T. Agar) is recommended for antibiotic sensitivity testing of fastidious pathogens such as Neisseria, Streptococcus and Haemophilus species with blood enrichment. Aneurine acts as vitamin source which favours the growth of several organisms especially Staphylococci.This medium is recommended for diagnostic as well as testing susceptibility of organisms to antibiotics and chemotherapeutic agents such as Sulfonamides.