iScreen Urine drug test kits are the least expensive and most flexible (meaning it is possible to test for many different drugs in different combinations) in testing drugs. Results of an iScreen urine drug test detect the presence or absence of specific drugs in the urine. A positive urine test result does not necessarily mean that the donor was under the influence of drugs at the time of the test. iScreen  can be defined as a rapid, one step screening test for the simultaneous, qualitative detection of multiple drugs and drug metabolites in human urine.

iScreen Drug Test 2 panel urine drug test is an immunoassay based on the principle of competitive binding. Drugs which may be present in the urine specimen compete against their respective drug conjugate for binding sites on their specific antibody. During testing, a urine specimen migrates upward by capillary action. A drug, if present in the urine specimen below its cut-off concentration, will not saturate the binding sites of its specific antibody. The antibody will then react with the drug-protein conjugate and a visible colored line will show up in the test line region of the specific drug strip. The presence of drug above the cut-off concentration will saturate all the binding sites of the antibody. Therefore, the colored line will not form in the test line region.