Drug testing services are services provided by companies or offices that assist in different methods of testing for numerous illegal substances in the human body. These companies are usually called diagnostic centers. There are numerous reasons why a person would be tested for such substances, including pending employment, probation, and for Workers' Compensation cases. Some instances require testing for all illegal substances while others include only a few. The different types of drug tests include urine sampling, blood tests, and hair follicle screenings.
The most common method of drug testing is through urine. When testing urine, a sample is taken from the patient and the temperature is tested to be sure it is between about 95° and 99° F (about 35° to 37° C), which are within the range of normal body temperature. Depending on whether or not the facility has a laboratory, the urine is then either tested on site or shipped to a laboratory for diagnosis.
Urine may be used to detect an array of different substances, including Tetrahydrocannibanol (THC) — the psychoactive substance in marijuana — methamphetamines, alcohol, cocaine, and opiates, such as heroin and prescription painkillers. Drug testing services offer different types of urine screens called 5 panel and 10 panel tests. A 5 panel test only tests for five substances, which are generally deemed the most common drugs that are abused. Conversely, a 10 panel test is an all-inclusive test that screens for ten different types of drugs typically accessible to the public.
Since urine testing is generally the cheapest and easiest way to screen for illicit drugs, it is the most commonly used procedure; however, it is not always the most reliable since many substances tend to leave the body within a matter of days. Urine is, however, effective in testing for marijuana because THC is fat soluble — meaning it is absorbed by fat molecules in the body — so it has a tendency to remain in the body longer than other substances and can be detected in the urine for a longer period of time.
Blood tests are also used by drug testing services where a blood sample is taken from the patient and either diagnosed on site or sent to a laboratory. A blood test typically screens for the same substances as urine tests but has a tendency to be more precise and allow less room for patient interference. Since products are sold to dilute urine, some people try to use such products to pass a urine test. It typically is much more difficult to change the chemical content of the blood.
Hair follicle screens are usually the most accurate type of drug test, as it can detect whether or not any drugs have been used within the previous 90 days. All major types of illegal substances can be detected through the hair follicle, with much more accuracy than other types of drug screens. While hair follicle testing is more expensive than urine and blood, the precision it offers has made it a more widely-used method. Not all drug testing services, however, include hair follicle testing.