What standard is used for preparing a bacterial suspension for sensitivity testing?

The McFarland standard is widely recognized and utilized for preparing bacterial suspensions for sensitivity testing. This standard provides a benchmark for the turbidity of bacterial suspensions, allowing for consistent and comparable results across different tests and laboratories. The McFarland scale typically includes a series of turbidity standards made from a barium sulfate solution, which produces a defined opacity when mixed with a bacterial culture.

By ensuring that the bacterial suspension matches the desired turbidity indicated by the McFarland standard, laboratory personnel can accurately determine the appropriate concentration of bacteria for sensitivity testing. This is critical for assessing the effectiveness of antibiotics against the specific bacterial isolate being tested. The use of an established standard helps maintain reliability and reproducibility in antimicrobial susceptibility testing, which is essential for treating infections effectively.