There are 3 tests that can be done to detect drug use: blood test, urine test and hair test. Toxicological tests are used to track the use of any psychoactive drug, such as marijuana, cocaine, ecstasy, barbiturates, opiates, and amphetamines.
Urine Test to Detect Drug Use
Drugs are usually metabolised by the liver and eliminated through the urine, hence detection is possible by this means.
However, the urine sample is usually only able to identify the recent use of drugs and does not allow distinguishing the occasional user from the dependent or who makes abusive use of drugs.
The period that the substances can be detected by the urine test varies according to the frequency and intensity of use, ranging from a few hours to about 30 days.
THE marijuana and cocaine are detectable for longer periods, while alcohol can only be screened if it has been used in the last few hours as it is metabolized and eliminated more rapidly.
However, the concentration of the drug in the urine is not presented. The result says only "positive" or "negative." The quantification of the drug is only made when requested, in specialized places.
How long after using the drug can it be detected in the urine?
- Amphetamine: 48 hs;
- Methamphetamine: 48 hs;
- Barbiturates:
- Short action: 24 hours;
- Intermediate action: 48-72 hrs;
- Prolonged action: 7 days or more;
- Benzodiazepines: 3 days;
- Cocaine: 2-3 days;
- Methadone: 3 days;
- Codeine / morphine: 48 hours;
- Marijuana:
- Single use: 3 days;
- Moderate use: 4 days;
- Daily use: 10 days;
- Chronic use: 21-27 days;
- Metaquoalone: 7 days or more;
- Phencyclidine (PCP): 8 days.
Blood Test to Detect Drug Use
The blood test detects the direct presence of the drug in the blood. Therefore, it is only capable of identify drugs that have been used very recently, a few hours ago.
Hair Testing to Detect Drug Use
The test that analyzes hair samples has dubious efficacy and so it is still not considered valid by doctors to verify the use of drugs.
The analysis is based on the fact that when a person uses drugs, part of the substance is carried by the blood that irrigates the scalp and deposited on the base of the hair strand.
When the hair grows, take with it the accumulated drug. Like this, every inch of hair would be equivalent to 1 month of consumption, allowing detection of drug use for several months.
It is important to remember that toxicological tests can only be carried out with the written consent of the person concerned or under emergency medical conditions.
