Advantages and Disadvantages of Presumptive Test - Essay Example

Advantages and disadvantages of presumptive testIntroductionPresumptive tests utilize target chemicals to determine the chances that a specific body tissue or body fluid is present. It is an analysis of a sample to establish whether that particular sample has a probability of becoming the substance in question or definitely not. The presumptive test applies particular methods to test for the presence of a specific substance (Houck & Siegel 2010, p. 331). For instance, the Kastle-Meyer test helps in determining that a sample is not blood.

Similarly, chemical testing is specific in determining and proving that a sample of a substance is blood. The presumptive test is a method that Forensic Drug Testing uses to analyze and determine drugs and other substances with unknown characteristics (Grine & Rackley 2010, p. 14). Forensic Drug Testing uses presumptive tests alongside confirmatory tests to analyze the unknown substance and determine its identity. However, presumptive tests have a number of advantages almost in the same measure as its disadvantages.

Advantages of Presumptive TestsPresumptive test yields immediate results to the testing staff. The staff, therefore, acquires instant snapshots of results and consequently decides on whether to issue a normal remedy or not (Paik 2011 p. 78). It is imperative that the test enables forensic drug tests to identify the possibility of a particular drug substance. The presumptive test applies principles of gas chromatography in isolating suspected drug from a given sample of blood. The second advantage that comes with a presumptive test is that it helps forensic drug test technicians to narrow down possibilities in the suspected substance (Grine & Rackley 2010, p.14). After narrowing down the number of possible tests, technicians can easily decide on which particular test to conduct rather than the use of many unguided trial and error experiments.

Limiting the number of possible tests is beneficial to an organization in terms of resource allocation and time. Similarly, presumptive tests help to minimize the number of materials and test reagents that trial and error tests would have absorbed.Forensic drug test technicians benefit from the ability of presumptive tests to identify evidence that naked eyes may fail to see. Ability to reveal chemical properties of sample analyte results from the use of various chemicals such as barium chloride reagent, potassium hydroxide and silver nitrate reagent (Paik 2011, p. 78). These reagents give technicians specific observable results that enable them to observe what naked eyes cannot observe.

Furthermore, the presumptive test provides room to examine a wide range of samples of substances. As a result, technicians manage to analyze many samples and determine their identity within a short range of time (DNA Analyst Training 2011, p. 1). Similarly, presumptive test also enables the technician to not only test samples of substances of a specific type, but from a variety of sources. Testing of a wide variety of substances is possible because of various methods, for instance, microscopic examinations, infrared and ultraviolet spectroscopy employed by presumptive tests.

However, despite the advantages associated with presumptive tests, it also has some limitations that make other methods such as confirmatory tests beneficial.