When it comes to hair follicle drug test, substances can be detected for several months or even years after consumption. The hair grows an average of one inch per month and traces of THC does not disappear. After three or four days, cannabinoids are completely eliminated from the blood. Urine screening allows the laboratory to identify occasional consumption until two to seven days later, and even longer in the case of regular consumption (seven to 21 days or more).
Saliva screening is sometimes used by the police for a check on motorists. It can detect a consumption dating from two to 10 hours. Its scientific reliability does not, however, reach consensus (existence of false positives). Whatever the test performed (blood, urine or saliva), they are aimed at detecting substances through the use of anti-THC antibodies, the presence of cannabinoid in the test fluid.
Depending on the type of test performed, a blood sample, urine (urine collection) or saliva (equivalent to a swab cotton swab), the user can employ various methods to prevent detection.
As an indication, it is estimated that the test is negative if the urinary concentration <25 to 50 ng/mL. The same applies to blood concentration <0.5 to 5 ng/mL (the blood test also quantifies 11OH-THC and THC-COOH). Salivary concentration <15 ng/mL (interpretation difficulties between 0.5 and 14.99 ng/mL).
Rapid drug testing can be done at home (and therefore anonymously), in a few minutes, without complex handling or sending to the laboratory. The issue of drugs is becoming a little more complex each year, with the proliferation of substances and risky behavior. Today, cannabis has become commonplace and that ecstasy pills are consumed in the evening with as little restraint.
It is therefore totally impossible for parents to know which drugs will be offered to their children. The same applies to associations that follow former addicts who are being weaned. If they choose to fall back on an alternative drug, it is impossible to know which one.
Paying attention to drugs in general, and not to a specific drug helps to avoid missing crucial information. Also, when one carries out frequent screenings with dissuasive purpose, the most effective method remains the tests of multi-drug screening, which is able to detect several drugs at the time.
The multi-drug tests have been specifically designed for this purpose; to make it possible to carry out a very wide prevention and covering all the drugs most used by young people and first-time consumers. They are very restrictive for people tested. No urine samples to be provided or blood taken in the laboratory. A simple salivary sampling is enough. They can detect drug use a few tens of minutes after the supposed intake.
In terms of pure efficacy, urinary tests are still a step ahead of salivary tests, even if they are reducing the gap.