Blood Agar Base 
CAT: AS‑1144
 
Overview
Blood Agar Base (CAT: AS‑1144) is the gold‑standard primary isolation medium in clinical microbiology. It is a highly enriched, non‑selective solid medium base designed for the cultivation of fastidious microorganisms and the detection of haemolytic reactions when supplemented with 5–10% defibrinated blood (sheep, horse, or human). Widely referenced in CLSI M100, ISO 11133, and FDA‑BAM, Blood Agar Base is also used in food, veterinary, and pharmaceutical laboratories for routine pathogen isolation and haemolysis studies.
 
Applications
Primary isolation of Streptococcus pyogenes, S. pneumoniae, Staphylococcus aureus, Haemophilus spp., Neisseria spp.
Detection of haemolysis types:
β‑haemolysis: clear zone (e.g., S. pyogenes, some S. aureus)
α‑haemolysis: green zone (e.g., S. pneumoniae, viridans streptococci)
γ‑haemolysis: no change (e.g., Enterococcus, coagulase‑negative staphylococci)
Base for chocolate agar, CAMP test, and antibiotic sensitivity assays (bacitracin, sulphonamide).
 
Key Features
Highly nutritious formulation (casein + soy peptone + yeast extract) for luxuriant growth.
Transparent agar surface allows clear observation of haemolysis zones.
Versatile supplementation: accepts blood from sheep, horse, or human sources.
Official reference medium in international standards (CLSI, ISO, FDA).
 
Composition (per liter)
Meat Extract: 10.0 g
Peptone: 10.0 g
Sodium Chloride: 5.0 g
Agar: 15.0 g
Final pH: 7.3 ± 0.2 at 25 °C
 
Supplement: Add 50–100 mL/L sterile defibrinated blood (5–10%) at 45–50 °C.
 
Preparation
Suspend 40 g of dehydrated base in 1 L purified water. Boil to dissolve completely. Autoclave at 121 °C for 15 minutes. Cool to 45–50 °C, add 5–10% sterile blood, mix gently (avoid foaming), and pour plates (~20 mL per 90 mm plate).
Incubation & Interpretation
Incubate at 35–37 °C for 18–24 h (5% CO₂ recommended).
Observe haemolysis patterns: β (clear), α (green), γ (no change).
 
Storage
Dehydrated base: Store in a cool, dry place below 30 °C.
Prepared plates: Store at 2–8 °C, sealed; use within 2–4 weeks depending on blood source.
 
Intended Use
For clinical, veterinary, food, and pharmaceutical microbiology. Not intended for diagnostic or therapeutic use in humans or animals.