Drug Testing Methodologies

Various kinds of drug tests are performed in a similar way. Firstly, the sample and the tamper-evident seal are checked on the subject of valid. If the individual tried to change the sample or adulterate it, or it has been damaged in process of carrying, the lab doesn't accept it.

Afterwards the sample is prepared to be corresponding with the conditions of drug testing. Urine and saliva samples can be used without any preparations, but, however, some types of tests require excluding some important components beforehand. Hair samples, sweat strips and blood must be turned to the appropriate condition. Lab assistants rinse the hair to remove all the second-hand toxins, the second step is to dissolve the keratin by enzymes. As for blood plasma, testing institutions often use centrifuge, to take away all the blood cells from the sample before testing. Sweat strips are usually disclosed and the device is put into the solvent to remove the toxins.

Drug test, held in the laboratories, consist of two steps. The first of them is the screening test, which is widely spread and used by labs for all the samples, coming through their hands. The second type is confirmation test, which is held only when the results shown after the screening test are positive. Immunoassay (EMIT, ELISA, and RIA are the most popular) is usually used to hold the screening drug test. It has been for the University of Illinois who has worked out the method for testing biological liquids for toxins. This first type of tests isn't rather accurate, sometimes the analysis can show wrong results both on negatives and positives. Two achieve exact results you need passing the confirmation test.

If the sample was proclaimed positive, it is marked in the lab and passed to the lab, where confirmation test is held. If the samples are negative, they're rejected and marked as negative. Mass spectrometry is widely used in most laboratories (and all SAMHSA licensed labs) to hold the confirmation test, it has a larger percent of being accurate, but accordingly it's far more expensive than the screening test. Positive samples, which have been detected negative during the confirmation test, are marked as negative. As for the samples, which have been detected positive during both tests, they're marked as positive. The institution, which has ordered the test, is informed about positive results. Many labs save the positive samples for a certain period of time, as they may be needed during law case or if appealed. [needs citation as to accuracy of tests]