In the Enzyme Multiplied Immunoassay Technique (EMIT), what does increased drug sample lead to?

In the Enzyme Multiplied Immunoassay Technique (EMIT), an increase in the concentration of the drug sample being tested leads to more enzyme activity. This is because EMIT is based on the principle of competitive binding between the drug in the sample and a labeled drug that is attached to an enzyme for detection. When the concentration of the drug in the sample rises, it competes more effectively with the labeled drug for binding sites on the antibody.

As more of the drug in the sample binds to the antibody, less of the enzyme-labeled drug is able to bind. However, because the assay measures enzyme activity, an increased drug sample causes an overall increase in enzyme activity indirectly through the reaction being measured, as the reduction in labeled enzyme competition increases the overall detection signal.

The detection mechanism relies on measuring the absorbance of the reaction product formed by the enzyme, which correlates with the concentration of the drug in the sample. Therefore, an increased drug concentration ultimately results in a higher level of enzyme activity, leading to a measurable output for analysis.