| Drug tests can involve taking samples of blood, | | | | There are a number of companies that offer kits |
| urine, breath or saliva for analysis. All of the tests | | | | for drug testing both for use by professionals and |
| are designed to detect small concentrations of | | | | for use at home. The drug tests kits offered |
| metabolites in the sample that will indicate if a | | | | include urine drug test kits, saliva drug test kits, |
| specific substance has been used recently. | | | | alcohol tests and digital breathalysers, and they |
| The body stores metabolites in fast growing cells | | | | can be bought on the internet. As these drug |
| and fatty cells, and eventually over time these | | | | testing kits are used privately there is little |
| metabolites leach out into the bloodstream and | | | | information on who is using them. |
| are excreted usually via the urine. | | | | On-the-spot drug test kits are generally portable |
| Different metabolites will stay in the body for | | | | devices and analyse a specimen of saliva, sweat |
| varying periods of time, and other factors which | | | | or urine. The use of a drug test kit involves a |
| can influence the rate of excretion are activity | | | | binding reaction between a drug and a |
| level, metabolism and the amount of fat a person | | | | pre-fabricated testing strip, which results in the |
| has in their body. | | | | strip changing colour. |
| In recent years, hair has received a lot of | | | | This reaction is usually visible within a few minutes |
| attention because it also stores metabolites and | | | | and indicates the presence or absence of a drug. |
| these cannot be removed by washing or | | | | As the tests only indicate whether a drug is |
| bleaching. It normally takes 5 days for metabolites | | | | present or not, not the actual amount, they are |
| to show up in the hair. | | | | not considered to be definitive analyses. However, |
| No drug test is perfect, but the most commonly | | | | the technology is improving rapidly and such kits |
| used drug test is urine analysis. There are many | | | | can achieve a high degree of accuracy. |
| drug test urine kits available, but its main | | | | Pupillometry is a new technique that uses eye |
| disadvantages are the ease with which samples | | | | responses to detect impairment due to drugs or |
| can be adulterated if unsupervised and its inability | | | | alcohol, although it should be borne in mind that |
| to detect current drug abuse. | | | | fatigue will also have an affect. |
| To overcome the problem of substitution or | | | | Laboratory testing allows the use of more |
| adulteration, some drug tests add a substance to | | | | sophisticated techniques. As with on-the-spot |
| a small portion of the sample and then re-check | | | | tests immunoassays can be used although these |
| the portion. If the urinalysis gives a negative result | | | | can be done on a large scale and automated in a |
| for the added substance, then the tester knows | | | | laboratory. |
| that the sample has been tampered with. | | | | However, the test that is considered the most |
| Drinking large amounts of water will also not help | | | | reliable for testing for drug use is gas |
| a person pass a drug test. Creatinine is a protein | | | | chromatography. This technique has the |
| that is naturally produced by the body and it is | | | | advantage that it can be used to quantify how |
| excreted in the urine at a fairly constant rate. | | | | much of the drug is present and also its |
| Therefore, if a person's creatinine levels are | | | | breakdown products. Gas chromatography can |
| unusually low this would generally indicate an | | | | identify specific drugs including prescription drugs in |
| attempt to flush their system of drug | | | | cases where other screening tests are only able |
| metabolites. | | | | to indicate the presence of a drug group. |