In particle-enhanced turbidimetric inhibition immunoassay methods, what happens when particle-bound drug binds to antibody?

In particle-enhanced turbidimetric inhibition immunoassay methods, the correct answer relates to the interaction between the particle-bound drug and the antibody. When the particle-bound drug binds to the antibody, it leads to an increase in light scattering. This occurs because the binding of the drug to the antibody forms larger immune complexes, which can scatter light more effectively than the smaller, unbound particles. As more particles aggregate due to the binding of the drug to the antibodies, the degree of light scattering increases, allowing for a quantifiable measure of the drug concentration in the sample.

This principle is fundamental to the method, as it takes advantage of the changes in turbidity (or cloudiness) in the solution to provide an indirect measurement of the concentration of the drug being tested. In these assays, the level of light scattering is directly related to the amount of drug present in the sample; thus, quantifying the scattering allows for the determination of drug levels.

The remaining options do not accurately describe the fundamental process at play during this type of assay. For instance, while magnetic separation may be a technique used in some immunoassays, it is not a necessary component in particle-enhanced turbidimetric inhibition assays specifically. Additionally, while