Presumptive drug test kits have been widely used all over the world, particularly by different law enforcement agencies as a quick, affordable, and relatively easy way of detecting the presence of illegal substances. However, it also has caught a lot of flak from its detractors due to its ability to produce false positives. While, these are serious allegations, presumptive test kits like those using a Scott reagent still continues to be employed by a lot of field testers. Visit their site now to have a better understanding on scott reagent.

Forensic Drug Chemistry: How it Works

Basically, field testers analyze a suspected unknown substance for the tell-tale signs of illegal drug activity. For example, using a Marquis reagent can cause most opium-based drugs turn purple. The same goes for Erlich reagent as it turns liquid blue in the presence of LSD. Thus, the goal of using presumptive tests is to determine whether there is a lawful cause to pursue further analysis and, thus, criminal charges in court.

The problem is that substances like cocaine share some chemical characteristics to more mundane products (i.e. caffeine), which can confuse a drug test kit. In this instance, the kit would most probably reveal a liquid blue solution – a false positive for Scott reagent.

Two Types of Forensic Drug Testing

There a reason why these tests are called ‘presumptive’ this is because the test is less precise and can only signal the field tester that there is a need to be highly suspicious of an individual who tested positive. To be able for the charges to hold in criminal court, samples must undergo a definitive confirmatory test. More commonly, a bulky and highly sophisticated laboratory equipment is employed: The Gas Chromatography Mass Spectrophotometer (GC-MS).

Of course, one cannot possibly expect every field tester to have a GC-MS everywhere they go. For one, GC-MS equipment is very bulky and heavy. Two, GC-MS are too expensive, which makes it highly impractical to buy one for every field tests.. So, while presumptive drug test kits has its own challenges, it still remains as the only viable and easy solution to determine the presence of illegal substances.