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Most people who take a drug test take a presumptive test, cheaper and faster than other methods of testing. However, it is less accurate and can render false results. The FDA recommends for confirmatory testing to be conducted and the placing of a warning label on the presumptive drug test: "This assay provides only a preliminary result.
There are different presumptive and confirmatory tests used for each type of biological material found at a scene. Presumptive tests are quick, sensitive and are relatively specific to bodily fluids that give the analyst an idea of what might be present. Confirmatory tests confirm what the biological sample is.
A presumptive test to detect saliva is the alpha-amylase test also known as the Phadebas Test. [4] This detection technique is based on the activity of the enzyme alpha-amylase which breaks down starches from food into smaller oligosaccharide molecules, starting digestion in the mouth. [ 11 ]
Despite the well-known problems with the kits, they're used in half of the roughly 1.5 million drug arrests in this country every year.
Hair drug testing is a method that can detect drug use over a much longer period of time than saliva, sweat or urine tests. Hair testing is also more robust with respect to tempering. Thus, hair sampling is preferred by the US military [66] and by many large corporations, which are subject to Drug-Free Workplace Act of 1988.
Presumptive, confirmative and completed [clarification needed] tests are a part of MPN. [citation needed] In molecular biology, a common application involves DNA templates diluted into polymerase chain reactions (PCR). Reactions only proceed when a template is present, allowing for a form of quantitative PCR, to assess the original ...
The above photo shows the positive results of the number 2 Marquis reagent presumptive drug test when used with a sample of opium. It is the primary presumptive test used in Ecstasy reagent testing kits. It can also be used to test for such substances as opiates (e.g. codeine, heroin), and phenethylamines (e.g. 2C-B, mescaline).
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. It relies on the peroxidase -like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into ...