Enzyme Multiplied Immunoassay Test
The enzyme multiplied immunoassay (EMIT) is a widely used analytical drug screening method that has been marketed for use by nonlaboratory personnel. The technique relies on the measurement of an enzyme's ability to modify a substrate. In its most common form, lysozyme that has been labeled with the suspected drug is added to the urine specimen along with a bacterial suspension and antibody to the suspected drug. If no drug is present, the antibody to the drug will bind with the druglysozyme ysozyme complex, thereby inactivating the lysozyme and failing to affect the turbidity of the suspension. If drug is present, the antibody to the drug will bind with both the enzyme-labeled drug and the free drug, leaving some of the enzyme-labeled drug complex free to act on the bacteria in the suspension, thus modifying the turbidity of the solution.
