2. Screening tests help detect disease in its earliest and most treatable stages.
3. Forensic labs are often called in to identify unknown powders, liquids and pills that may be illicit drugs. There are basically two categories of forensic tests used to analyze drugs and other unknown substances: Presumptive tests (such as color tests) give only an indication of which type of substance is present -- but they can't specifically identify the substance.
4. Microcrystalline tests involve exposing the substance to a reagent and then examining the color and morphology (including shape) of the crystals that form. It is much more specific than color tests in identifying a particular drug as the size, color, and shape of the crystals will differ for each specific drug.
5. Different drugs and materials absorb UV and ultraviolet light differently. This provides another way for forensic scientists to examine materials. Like color tests, UV spectrophotometry cannot positively identify a particular drug, as there may be other materials with the drug that could influence the results. However, the test is a very useful one when determining if a drug is present. A spectrophotometry device can emit both UV and infrared light as it measures how a sample either reflects or absorbs the light. Though ultraviolet spectrophotometry cannot positively identify a drug, infrared spectrophotometry can, since the pattern of light is unique to each type of compound.
6. Forensic scientists can use different types of tests to identify a substance in a suspected meth lab, when someone is caught with a possible drug they can help prove that they did in