Search results
Results from the WOW.Com Content Network
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.
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. In addition to looking for biological material at a crime scene, pieces of evidence can also be examined and analyzed for the presence of DNA.
As with all presumptive tests, this technique can produce false positive results due to metals and strong chemicals, such as bleach, that will also react. Another common presumptive test is the Kastle-Meyer or Phenolphthalein test. This is a catalytic test that detects the heme group in blood that transports oxygen and carbon dioxide. [5]
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 ...
The national public health agency is aware of the presumptive positive case of H5 avian influenza in a child, a CDC spokesperson USA TODAY Wednesday, is "awaiting the specimen to test at its lab ...
New York’s prison system unfairly punished more than 2,000 prisoners after tests of suspected contraband substances falsely tested positive for drugs, according to a report released Thursday.
The stunning rally in US stocks this year caught Wall Street's top forecasters off guard, with most analysts far less upbeat heading into 2024.