Several types of drug tests are used to determine whether you have been ingesting drugs.  The different drug tests each have pros and cons that will determine which one is used on different occasions.  Since drug use can be detected in hair, body fluids and hair, drug testing can be done on specimens of your hair, urine, blood, saliva, and sweat.   

Hair specimens can tell much about your use of a wide variety of drugs, including marijuana.  Not only can hair specimens reveal information about a variety of the drugs that you may have been ingested, hair specimens will provide a history of your recreational drug use depending on how long the hair specimen is.  The only information that hair specimens may not provide is that concerning your most recent use of drugs. 

Testing blood for drugs will give an accurate picture of your drug use.  The high price of blood tests and the invasiveness of the blood test prohibit many companies from using this drug test.  Both sweat and saliva can be tested for drug use and although accurate, are not widely used.  The most popular method for drug tests because of its relatively low price is the urine test, which can detect recent use.   

When the urine test is used, the person being tested has some ability to tamper with the test results so usually the person is monitored before and during the urine test to prevent such tampering.  If a person tries to flush out their urine beforehand by drinking plenty of fluids, this may alert the tester that another test is in order.   

Drug tests will test for different drugs in the five main drug categories.  These drug categories are for cannabinoids, cocaine, amphetamines, opiates, and phencyclidine.  These drug categories include the drugs that are made from or a combination of those five categories of drugs.  There are also further drug tests, which will detect consumption of alcohol, barbiturates, benzodiazepines, hydrocodone, MDMA, methadone, methaqualone, and propoxyphene.   

Cost and level of invasiveness will be deciding factors in the drug test that is chosen.  If your company does drug tests, it is in your best interests to find out what types of drug tests that the company will administer.  With this type of information, you will be better prepared if it is your name that comes up for the next drug test.