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Drug Testing Basics
by Erowid
v 1.5 - Sep 27, 2012

  1. What do they Test for?
  2. Test Types
  3. Test Sensitivity
  4. Detection Periods

The first thing to know about drug testing is what the standard test looks for. What is being tested for varies greatly based on testing company, expense, expectations, federal requirements, etc. Following is a description of what to expect from the standard tests.

The SAMHSA-5 #
Federal government guidelines (by SAMHSA-the Substance Abuse and Mental Health Services Administration) require that companies which use commercial class drivers licenses for employees must have a testing system in place. Among other things, this required testing program must test for 5 specific categories of drugs (referred to as the "SAMHSA 5", previously called the "NIDA-5"). Because of this federal requirement, most drug testing companies offer a basic drug test that checks for drugs in these 5 common categories. Click on the substance name for a description of the laboratory method for detecting the substance.
  1. Cannabinoids (marijuana, hash)
  2. Cocaine (cocaine, crack, benzoylecognine)
  3. Amphetamines (amphetamines, methamphetamines, speed) - does not include MDMA/MDA/MDE
  4. Opiates (heroin, opium, codeine, morphine)
  5. Phencyclidine (PCP)
U.S. Department of Transportation (DOT) Standard Tests #
Starting in October, 2010, the US DOT added MDMA, MDA, and MDE (MDEA) to their standard 5-panel drug testing, by adding the ecstasy-type drugs to the amphetamine section of their test panel. See DOT Drug Testing: On and After Oct 1, 2010 - Still a 5 Panel.

Expanded Tests
Most drug testing companies also offer an expanded test which includes a few additional drug classes and specific drugs in the testing process. Most do not add all of these in their expanded test, but choose a different combination of 3 or 4 to add :
  1. Barbiturates (Phenobarbital, Secobarbitol, Butalbital)
  2. Hydrocodone (Lortab, Vicodin)
  3. Methaqualone (Quaaludes)
  4. Benzodiazepines (Valium, Xanax, Librium, Serax, Rohypnol)
  5. Methadone
  6. Propoxyphene (Darvon compounds)
  7. Ethanol (Alcohol)
  8. MDMA (Ecstasy)
Additional Testables
In addition, there are a few other substances which it is possible but quite unusual to test for. I only found reference to testing for these additional substances at 1 (out of 15) drug testing sites :
  1. LSD
  2. Tryptamines (Psilocybin, AMT, DMT, DPT, 5-MeO-DiPT)
  3. Phenethylamines (Mescaline, MDMA, MDA, MDE, 2C-B, 2C-T-7)
  4. Inhalents (Toluene, Xylene, Benzene)
There are five primary types of drug tests: urine, blood, hair, saliva, and sweat. Most common is the urine test which has the benefit of being inexpensive and less intrusive than the blood test.

Urine Tests
  • Are the least expensive of the test methods (~$7-$50 for home version).
  • Are considered an intrusive method of testing.
  • Can be done at home (for example by parents) though require lab verification for accurate results.
  • Detect use primarily within the past week (longer with regular use).
  • Can be affected by abstaining from use for a period of time before the test.
  • Are often temperature tested to insure sample integrity.
Saliva Tests
  • Are a little more expensive than urine testing, but less than hair or blood. (~$15-$75).
  • Are considered a relatively unintrusive method of drug testing.
  • Are becoming more common.
  • Are easy to administer but require lab processing to ensure accuracy.
  • Detect use primarily within the past few days.
  • Can detect more recent use than other testing methods.
  • Have no nationally accepted standards or cutoff concentrations for detection, making results greatly dependent on the specific product purchased. This could also make results less-reliable and/or acceptable for legal cases.
  • More reliable for detection of Methamphetamine and Opiates, less reliable for THC or Cannabinoids (2004).
Hair Tests
  • Are currently several times more expensive than urine tests (~$100-$150).
  • Are considered a relatively unintrusive method of drug testing.
  • Detect substance use over a longer period (see detection period).
  • Do not usually detect use within the past week.
  • Require a sample of hair about the diameter of a pencil and 1.5 inches long. They can not be done with a single hair.
  • Test positive a little more than twice as often as a urine test. In a recent study, out of 1823 paired hair and urine samples, 57 urine samples tested positive for drugs of abuse; while 124 hair samples from the same group tested positive.
  • Are not significantly affected by brief periods of abstinence from drugs.
  • Can sometimes be used to determine when use occured and if it has been discontinued. Drugs, such as opiates (codeine, morphine, heroin) lay down on the hair shaft very tightly and are shown not to migrate along the shaft, thus, if a long segment of hair is available one can draw some "relative" conclusions about when the use occurred. However cocaine, although very easy to detect, is able to migrate along the shaft; making it very difficult to determine when the drug was used and for how long.
  • Claims to be able to reliably differentiate between opiate and poppy seed use.
  • We've heard that many hair tests now check for more than the SAMHSA-5, and include at least Cannabis, Ecstasy/MDMA, Cocaine, Opiates, Methamphetamine, Amphetamine, Phencyclidine (PCP), Benzodiazepines, & Barbiturates (2001).
  • Shampoos and "follicle cleansing" products do not reliably remove drug metabolites from hair.
  • Hair/follicle tests as of 2011 are able to detect use for months (sometimes more than a year) after use.
Blood Tests
  • Are the most expensive method of testing.
  • Are considered the most intrusive method of testing.
  • Are the most accurate method of testing.
  • Are the least common method of testing (most likely due to cost).
Sweat (Patch) Tests
  • Are considered a relatively intrusive method of drug testing because they require the wearing of a patch for an extended period of time.
  • Are still relatively uncommon.
  • Are controversial in terms of accuracy. There is some reason to believe that surface contamination (such as cannabis smoke) can cause a false reading.
  • Can detect use which would not trigger other tests. Because of the short detection period for many drugs in urine, single use of many drugs longer than a week prior to using the patch will not cause a positive urine test. Because the skin patches are gathering sweat over an extended period of time, it is possible that any use during that time will produce a positive result.
The Substance Abuse and Mental Health Services Association (SAMHSA) provides guidelines for what qualifies as a positive drug test. If a test does not give results higher than the guidelines, it does not qualify as a "positive" test. If an immunoassay test gives positive results, a second Gas Chromatography test must also give positive results before a result of "positive" is announced. The following chart shows the guidelines by substance.

Initial Test Cutoff Concentration
Confirming Test
(GC / MS)
Cannabis50 ng/ml15 ng/ml
Cocaine300 ng/ml150 ng/ml
Opiates2000 ng/ml2000 ng/ml (morphine)
2000 (codeine)
Amphetamines1000 ng/ml500 ng/ml
PCP25 ng/ml25 ng/ml
Notes: Cannabis is detected through its metabolite Delta-9-tetrahydrocannabinol-9-carboxylic acid. Cocaine is detected by its metabolite Benzoylecgonine. Methamphetamine positive confirming test requires both 500ng/ml of methamphetamine and 200ng/ml of amphetamine.
from SAMHSA Feb 2005, 69 FR 19644

Some companies are getting around these guidelines by reporting the levels found without categorizing them as a "positive" or "negative" test. This seems to be a problem primarily with mail-in home tests rather than corporate testing.

SAMHSA's testing protocol also requires that labs verify the 'validity' of the urine samples collected to check to make sure they are not adulterated or have been tampered with to interfere with the results. They require that the lab "(1) Determine the creatinine concentration on every specimen; (2) Determine the specific gravity on every specimen for which the creatinine concentration is less than 20 mg/dL; (3) Determine the pH on every specimen; (4) Perform one or more validity tests for oxidizing adulterants on every specimen; and (5) Perform additional validity tests when the following conditions are observed: (i) Abnormal physical characteristics; (ii) Reactions or responses characteristic of an adulterant obtained during initial or confirmatory drug tests (e.g., non-recovery of internal standards, unusual response); or (iii) Possible unidentified interfering substance or adulterant. The choice of additional validity tests is dependent on the observed indicators or characteristics as described in (i), (ii), and (iii) of this section.". Source Federal Register: April 13, 2004 (Volume 69, Number 71), Page 19659.

The following chart gives approximate detection periods for each substance by test type. The ranges depend on amount and frequency of use, metabolic rate, body mass, age, overall health, drug tolerance, and urine pH.

 Shortest Detectability - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Longest Detectability
Alcohol12 hrs6-12 hrsunknown6-24 hrs (5 days with EtG)n/a
Amphetamine12 hrs3 daysunknown1-4 daysup to 90 days
Barbituratesunknownunknownunknown1-21 daysunknown
Benzodiazepinesunknownunknownunknown1-42 daysunknown
Cannabis (smoked--single use)1-3 days12-24 hrsunknown1-3 days0 to 90 days
Cannabis (smoked--regular use)1-2 weeks12-24 hrsunknown15-50 daysup to 90 days
Cannabis (oral--single use)2-7 daysunknownunknownunknown
Cocaineunknown1 dayunknown4-5 daysup to 90 days
Codeine/Morphineunknown12-36 hrsunknown2-4 daysup to 90 days
Heroinunknownunknownunknown2-4 daysup to 90 days
MDMA (Ecstasy)1 - 3 days3 daysunknown1-5 daysup to 90 days
Methamphetamine1-3 daysunknownunknown3-5 daysup to 90 days
PCP1-3 days3 daysunknown3-7 daysup to 90 days