Turbidimetric assays are used to determine the influence of an antibiotic on the growth rate of a target microorganism in a specific medium. All components are added to a tube. Then, the inhibition of growth of the microorganism due to the antibiotic is measured by the turbidity of the solution.
The following image shows the potency estimation of a Test and Control sample in a turbidimetric assay: Every rack contains the five concentration steps of the Standard (S1, S2, S3, S4, S5), and the Test (U3) and Control (CTL1) sample. Potency values of Test and Control Sample are interpolated based on the Reference step (S3).