McFARLAND STANDARD SET (Each Set Contains 1 Tube of 0.5, 1, 2, 3, 4 Mcfarland Standard)

McFarland Standard Kit is used to standardize approximate concentration of bacteria in a liquid suspension by comparing the turbidity to a McFarland Standard. It is frequently used in the preparation of bacterial inocula for microbiological procedures that require a uniform cell concentration.
McFarland Standards are prepared by mixing barium chloride with sulfuric acid to produce a fine precipitate of barium sulfate. The precipitate, when uniformly dispersed, produces a turbidity that can be visually compared to a suspension of bacteria of known concentration.
The 0.5 McFarland Standard is commonly used in clinical microbiology, especially for antimicrobial susceptibility testing and for evaluating the performance of culture media. Prior to use the standard should be mixed thoroughly to ensure the barium sulfate is uniformly distributed.
For comparison, the test suspension and standard are transferred to tubes of identical size and diameter. The turbidity can then be visually compared under suitable lighting, using a Wickerham card or similar reference. If the suspension is too light, more organisms may be added. If it is too dense, sterile broth or saline can be added until the desired turbidity is achieved. Proper mixing, tube selection, and controlled preparation help improve consistency during inoculum standardization.

Helps standardize bacterial suspension turbidity by comparing test inocula with a known McFarland reference for consistent microbiological testing.