No mixing, no preparation and no reagents. THC metabolites in the urine sample compete with specially colored antigens impregnated in the test strip. The strip is specially calibrated so that a concentration above the NIDA cutoff is required to yield a positive result. This technology is FDA approved for forensic use and is as accurate as the screens used by government agencies, state and federal correction facilities, probation and parole offices, and employers across the country. How Immunoassays Work Immunoassays have been used in drug screening for more than 20 years.
Immunoassays use antibodies to detect the presence of drugs.
An antibody is a protein that will react only when combined with a specific substance or very similar substances. In using immunoassays in drug testing, the targeted drug acts as the antigen. The tag is the material that shows the red color on the test strip. The tagged antigen and antibodies are chemically planted on the test strip. The untagged antigen would then have to compete with the tagged antigen to react with the antibodies.