Multi-panel saliva drug testing is one of the simple methods to detect the drug abuse. After urine drug test kits, the multi-panel saliva drug test kits became popular because of their ease in use and instant drug detection. The test kit consists of two simple things like the collector and the testing device. The collector is used to collect the sample from the suspect and by inserting it in the testing device we can read the results within few minutes. Let us see the principle behind this test and how it detects multiple drugs at a single shot.
Since many of the drugs are consumed orally, the drug and its metabolites which are in the oral fluids are used to detect the use of drugs. When the collector having the sample is inserted into the testing device, a portion of the oral fluid specimen migrates upward by capillary action. If the sample contains drug or its metabolites, below the cut-off concentration, it will not saturate the binding sites of the specific drugs, allowing the antibody to react with the drug protein conjugate, which further results in the appearance of colored line in the test region. Hence a colored line in the test region of the specific drug represents the absence of that drug in the provided sample.
In case if the drug or its metabolites are present more in the sample than the required cut-off then, the specimen will saturate with the binding sites of the antibody and hence no colored line will be displayed in the test region. Hence, for a positive test there will be no colored line in the test region and the drugs whose test area is empty are found to be abused by the donor. However, to make us confident that the process is complete, a colored line will always be displayed in the control region (C) both for positive and negative tests.