How long after consumption can drugs be detected in urine?

All drugs that enter the human body are metabolized in the liver (transformed into removable substances called metabolites) and eliminated by the kidney (although they can also be eliminated through feces, sweat, etc.). Therefore, they are detectable in urine. The time during which the consumed drug can be detected in the urine depends on several factors: if it is stored in fat, if it is metabolized at a different rate, etc. 

This gives an approximate time for each drug *:

  • Alcohol 12 hours
  • Amphetamines 4 days
  • Benzodiazepines 7-10 days
  • Cocaine 4 days
  • Codeine 7 days
  • Heroin 4 days
  • Marijuana 30 days
  • Methadone 10 days
Reasons the test is done

The test is done to detect the presence of illicit drugs and some prescription drugs in your urine. Their presence indicates that you recently used these drugs. Some drugs can stay in your system for several weeks, so the screening test must be interpreted carefully.

Common types of drug tests

Urinalysis, also known as urinalysis, is a procedure that requires one to provide a urine sample. Either a test card is used on site for immediate results, or the sample is sent to a laboratory to undergo gas chromatography or mass spectrometry, also known as GCMS. It is known as high performance liquid chromatography or immunoassay analysis. Sample substitution or adulteration have become a major problem in the United States, due to the prevalence of drug-free or its really work real urine to pass drug test synthetic urine and a wide range of adulterants on the Internet. Some people try to pass a urine test by drinking plenty of water. However, a sufficiently diluted sample may be rejected due to its light color. Too clear samples can be marked and tested for specific gravity, but if the sample fails the specific gravity test, the sample is rejected and the dilution is reported to the entity that ordered the test.

Hair drug testing is fairly accurate and can come back 6 months or more. It shows controlled substances that are used in this time frame. As the hair grows out, they use drugs that are encased in the hair shaft, so the longer the hair, the longer back in the drug history the laboratory person can detect. Most legitimate test facilities only use hair within approximately 3-5 cm of the scalp, and discard the rest. This limits the detection history to approximately 90 days, depending on the person’s hair growth rate. Some people try to get around this by shaving their head. In the absence of the required amount of hair on the scalp, body hair can be used as an acceptable substitute for results. Additionally, for pre-employment hair testing, failure to obtain a sample may be grounds for not recruiting the individual drug abuse suspect.

Oral Fluid Drug Screening and Drug Saliva Screen – Oral fluid based drug tests can generally detect use during the preceding days. Oral fluid or salivation based drug tests are becoming more and more frequent due to their convenience and the fact that they cannot be adulterated. Moreover, in the place of oral based tests, in particular, allow the execution of random testing programs, proven to be the most effective type of drug detection. Oral fluid-based tests are as accurate as urine and can be obtained from quality suppliers in the United States. The test is generally performed by employers, whether for pre-employment, random, post-accident, reasonable suspicion, or return-to-work tests.

Sweat drug screens are patches attached to the skin to collect sweat over a period of time, most commonly 10-14 days. These are used almost exclusively by child protective services, probation departments, and other government institutions related to drug use for long periods, especially when urinalysis is not practical. The patches have security features that prevent them from being covertly removed and then reapplied without the knowledge of the testing agency, and at the end of the testing period, the patch is removed by a probation officer or social worker and they are sent to the laboratory for analysis. If the person has used drugs during the period that the patch was in place, they go to a positive result for the drug. This type of testing has fallen out of favor with government agencies, due to documented problems with some drugs.