Blood Agar with 5% Sheep Blood - Diagnostic Gold Standard

Blood Agar with 5% defibrinated sheep blood serves as the cornerstone primary isolation medium in clinical microbiology. The optimal sheep blood concentration balances nutritional enrichment with clear hemolytic pattern visualization - beta-hemolytic streptococci show complete clearing, alpha-hemolytic organisms display greenish pigmentation, and gamma-hemolytic bacteria maintain intact erythrocytes.

Critical Diagnostic Applications

This enriched medium provides essential hemin (X-factor) and NAD (V-factor) for fastidious pathogens while enabling definitive streptococcal grouping. Primary applications include respiratory pathogen isolation (Streptococcus pneumoniae, Haemophilus influenzae), wound infection analysis, and blood culture subculture workup.

The medium excels in mixed flora differentiation, supporting superior recovery of Staphylococcus aureus, beta-hemolytic streptococci (Groups A, B, C, G), and Enterococcus species from clinical specimens. Enhanced pigment production facilitates preliminary identification.

Technical Superiority

Standardized 19mm x 15mm x 20ml plates (Cat. 0802100E) in 10-piece stacks. SFDA compliant, ISO 13485 manufactured with uniform blood distribution and optimal oxygen tension. Quality control verified with S. pyogenes ATCC 19615 (beta-hemolysis), S. pneumoniae ATCC 49619 (alpha-hemolysis).

Optimized Laboratory Protocol

Primary inoculation using four-quadrant streak technique. Incubate in 5-10% CO2 at 35-37°C for 24-48 hours. Examine under adequate lighting for hemolytic reactions, colony morphology, and satellitism phenomena. Essential backup medium for automated blood culture systems and comprehensive respiratory panels.