Drug Test Overview

Drug tests are common in many workplaces as employers seek to determine whether a new potential employee or an existing employee is using or abusing illicit drugs. Drug testing by parents has grown in popularity since the advent of home drug testing kits and the relative affordability of such test kits in recent years.

Common Questions

The most common questions posted to forum discussion boards typically revolve around users wondering "how long do drugs stay in your system?" or something specific such as "how long will marijuana stay in my system?". Typically these questions are posed by drug users who have no intention of quitting and simply want to beat a drug test for the purpose of gaining employment, not getting in trouble with their probation or parole officer, or avoiding detection by their parents. First, the real answer is getting permanent help for alcohol or drug addiction. Second, the answer is simply that it nearly always varies based on a number of factors such as your height, weight, body fat, level of physical activity, and other factors such as dosage, potency, and consistency of use.

Types of Drug Tests

The majority of drug tests are urine tests. There are two types.

Screening Type
Substance Tested / Comments
Standard Urine Tests
  • Cannabinoids (cannabis, marijuana, hash) A marijuana drug test specifically looks for the level of THC (Tetrahydrocannabinol) in your body.
  • Amphetamines (amphetamines, methamphetamine)
  • Cocaine (cocaine hydrochloride, crack)
  • Opiates (heroin, opium, morphine, codeine)
  • PCP (pencyclidene)
Advanced Urine Tests
  • Barbiturates (phenobarbital)
  • Qualuudes (methaqualone)
  • Benzodiazepines (valium, rohypnol)
  • Methadone
  • Ethanol (alcohol, beer, wine, liquor)
Hair Tests
  • Can detect most drugs up to 90 days after use.
Blood Tests
  • are rare, expensive and usually only done in criminal investigations
Other Tests
  • Mouth swabs and saliva samples can be analyzed for drug use but these are less effective

Passing a Drug Test Tricks

Parents and employers conducting non-clinical drug testing should be aware that users frequently consume products that aid in rendering a marijuana drug test (ext. link) inaccurate.


Standard Tests
Detection Period (hrs)
Y 24-72 False positives may be caused by a variety of over-the-shelf & prescription medicines - see full list here
Y 48-72
Can be detected up to 12 weeks in a chronic user
Y 48-120 Longer times will be observed in the habituated person using large quantities
Ecstasy (MDMA)
Ecstasy Drug Testing
N 24-72 Can be detected by a test for Amphetamines
Heroin (Opiates)
Y 24-48 Several over the counter medicines may cause false positives in heroin drug tests - list here
N Unknown Tests for K are extremely unlikely
More on LSD drug testing here
N 24-48 Very unlikely test as amounts used are microscopic
Mushrooms (Psilocybin)
Magic Mushrooms Drug Test
N unknown Very unlikely test
Y 24-96 Dependant on factors such as amount used, fluid intake, excretion, and urinary pH

About Testing Positive for Drugs or Alcohol

To test positive for drugs or alcohol, an initial screening test and a follow-up one must show the same result. People interested in being hired by federal agencies must be prepared to undergo a drug screening as part of the hiring process. A company hiring commercial truck drivers is required to test employees operating vehicles following an accident or for cause. A positive drug or alcohol test may mean loss of a job or the opportunity to work in certain areas.

About Testing Negative for Drugs or Alcohol

A negative test for drugs or alcohol doesn't necessarily mean that no evidence of substance abuse was found in the sample provided by the subject. It indicates that any amount detected is lower than the cutoff established for that drug. A negative drug test indicating any level of a controlled substance should be taken as a red flag that the subject is at risk for a positive result if the test were repeated. After dodging that bullet, it may be time to reconsider whether continuing to use is worth the risk.


Detectable in Saliva
Detection Period (hours)
Detectable in Urine
Detection Period (days)
Detectable in Hair
Detection Period (days)
Amphetamine (AMP)
5-10 min after use 72 2-5 hours after use 2-4 5-7 days after use 90
Methamphetamine (mAMP)
5-10 min after use 72 2-5 hours after use 3-5 5-7 days after use 90
Cocaine (COC)
5-10 min after use 24 2-5 hours after use 2-4 5-7 days after use 90
Opiates, Heroin (OPI)
1 hour after use 7-21 2-5 hours after use 2-4 5-7 days after use 90
Marijuana (THC)
1 hour after use 12 2-5 hours after use 15-30 5-7 days after use 90
Phencyclidine (PCP)
- 24-72 2-5 hours after use 7-14 5-7 days after use 90
Benzodiazepines (BZO)
- - 2-5 hours after use 3-7 - -
Ecstasy (MDMA)
- - 2-5 hours after use 1-3 5-7 days after use 90
Barbiturates (BAR)
- - 2-5 hours after use 4-7 - -
Methadone (MTD)
- - 2-5 hours after use 3-5 - -
Oxycodone (OXY)
- - 2-5 hours after use 2-4 5-7 days after use 90

***This information is taken from government sponsored sources as well as package inserts from popular Saliva, Urine, and Hair Tests. This chart and these stats should be taken only as a general guide - detection times will vary based on a number of factors including frequency of use, route of administration, body mass, and age.

Alcohol Tests

Have you ever been asked to provide a breath sample during a traffic stop by police? If so, you have been given an alcohol test. Employers and school administrators may also be interested in finding out whether a job applicant or a student uses alcohol regularly and may use a number of methods to find out this valuable information, including testing blood, saliva and hair.

Marijuana Drug Tests

Marijuana is a commonly-used illegal drug and a number of people who are asked to undergo a drug test don't think about their pot use when they provide a sample. Drug tests can detect the presence of THC, the ingredient that gives pot smokers their high, quite easily, since it stays in the user's system for some time - as long as 30 days in some cases.

Cocaine Drug Tests

Cocaine tests look for the presence of benzoylecgonine in urine. Using this substance can be detected up to 60 hours after the last time the drug was used. If a hair test is conducted, it can show a prior history of coke use even if the subject has already stopped using the drug.

Ready to Quit? Detoxing is the First Step

Learn more about the detox and withdrawal recovery process, and explore our directory of detox centers across the US by following a link below.