Home Products Most Popular Contact
No items in your cart.
The page below is a sample from the LabCE course Drug Testing Methods in the Clinical Toxicology Laboratory. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Drug Testing Methods in the Clinical Toxicology Laboratory (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 111 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart

Immunoassay Techniques Used in Drug Test Screening: Enzyme-linked Immunosorbent Assay (ELISA)

In enzyme-linked immunosorbent assay (ELISA), the antibody is absorbed on a solid surface. The urine sample and drug or metabolite labeled with enzyme are added to a testing well where drug or metabolite in the sample and drug or metabolite labeled with enzyme compete for binding sites on the antibody that is absorbed to the surface of the well. Unbound components are removed by washing the well and a chromogenic reagent is added. A colored by product is formed when it reacts with the drug or metabolite labeled with enzyme that has bound to the immobilized antibody. The absorbance reading on the spectrometer is inversely proportional to the concentration of drug or metabolite in the urine sample.