Table of Contents

Drug tests detect drugs as well as metabolites. Metabolites are the byproducts of a substance after it has run through your system. To determine whether you will pass or not, it is important to know how much of the illicit metabolites are in your urine and how much is tested for. Table 1.2 will give you an approximation; however, it varies depending on a number of factors. Testing method and levels tested for are major factors.

1.1 Halflife of TetraHydraCannabinol: The halflife of THC concentration ranges between 0.8 to 9.8 days. There is too much human variation to even approximate how long THC will be detected in the urine of an individual. Infrequent users with a fast metabolism will have the shortest detection time. Frequent users with a slow metabolism will have long detection times. The only way to estimate a detection time is to consider the lower and upper bounds (3-30 days), and decide based on the factors I've mentioned.

1.2 Detection times of several drugs.

Approximate Detection Time in Urine using EMIT:

Amphetamines 2-4 days
Barbituates
Short-Acting (ie. secobarbital) 1 day
Long-Acting (ie. phenobarbital) 2-3 weeks
Benzodiazepines 3-7 days
Cannabinoids 3-30 days
Clenbuterol [PE] 2-4 days [F1]
Cocaine 2-4 days
Codeine 2-5 days
Euphorics (MDMA,psilocybin) 1-3 days [F2]
LSD 1-4 days [F6]
Methadone 3-5 days
Methaqualone 14 days
Nicotine ? [F5]
Opiates 2-4 days
Peptide hormones [PE] undetectable
Phencyclidine (PCP) 2-4 days [F4]
Phenobarbital 10-20 days
Propoxyphene 6 hours to 2 days
Steroids (anabolic) [PE] oral: 14 days [F3]

parenterally: 1 month [F3]
[PE] Performance Enhancers
[F1] 0.5 ng/mL by GC/MS
[F2] By RIA and GC/MS only. Not Detectable by EMIT.
[F3] By HPLC, RIA, and GC/MS. Not Detectable by EMIT.
[F4] 8-14 days as was reported in earlier versions and was incorrect.
[F5] No data available yet. I expect the detection time to be long because nicotine is fat soluble.
[F6] Detectable by EMIT and RIA, but rarely tested. A lab will only test for LSD when specifically requested.

Note: Detection times vary depending on analytical method used, drug metabolism, tolerance, patient's condition, fluid intake and method and frequency of ingestion. These are general guidelines only.

Other factors determining degree of intoxication include metabolism, tolerance, frequency of intake, fluid intake, amount of marijuana, potency of marijuana, and length of time you've been a user. If you use marijuana on rare occasions, your urine may be clean of metabolites in less than a week. There is a common and strange phenomena that occurs with chronic users. You would expect a chronic user to have the longest detection time and the smallest chance of passing.

This is not always the case. A chronic user with a high tolerance will eliminate drugs quicker than an occasional user. Chronic users have tested negative after a week long binge. Lipid tissue also makes a huge difference. Skinny users not only have a faster metabolism (usually), but also lack storage for THC metabolites. Fat will cause a lag in excretion pattern, and lead to a longer detection time. You should now be able to understand why an individuals detection time for THC is so unpredictable. Please don't post or e-mail a question "how long will it take..." This is the single most frequently asked question. Many people can't even begin to estimate a detection for their own bodys, let alone the unseen, unknown body of a lost internet explorer.

1.3 Positive (defined): 50 nanograms of THC metabolites per milliliter defines a "presumptive positive" by NIDA certified labs. This value was originally 20 ng/mL, but too many false positives resulted. So the level was raised to 100 ng/mL to reduce false positives. As of January 1995, the threshold was lowered back down to 50 ng/mL because drinking water would easily bring a positive below 100 ng. Be aware that these cutoffs are not universally consistent. I recently heard of a lab using a 15 ng/mL cutoff! Following is a table for cutoffs of other drugs:

[TABLE 1.3]

DRUG SCREENING CUTOFF GC/MS CUTOFF
Amphetamines Class 500 500
Amphetamine 500
Methamphetamine 200
Barbituates 200 100
Cocaine 150 150
Marijuana 50 15
Opiates 300
Codeine 300
Morphine 300
Phenyclidine 25 25

All cutoff levels are in nanograms/mL:
1.3.1 Passive smoke and positives: "Second hand marijuana smoke in a car can cause you to fail the next day" (Nightbyrd). It is possible that second hand [marijuana] smoke will raise someone to the 50 ng/mL level; however, *extreme* exposure is required. For instance, a closed car full of pot smokers and a non-smoker may render the non-smoker positive for both urinalysis and the hair test, provided that they are sealed in the car for a while. The Army did a case study where volunteers were put in a room pumped full of smoke for an hour, five time daily. Subjects started testing positive after the second day. The non-smoker would have to take in virtually as much second hand smoke as a smoker. Non-smokers are safe in a ventilated area, as long as they don't get a hair test. According to Clinton, simply blowing crack smoke on ones hair may cause a positive hair test. Second hand pot smoke doesn't affect the hair test results as much as crack smoke does mainly because exhaled smoke contains no THC. The only pot smoke that contains THC is the smoke that hasn't entered the lungs.

1.4 Decreasing detection times: Increasing metabolism is probably the most effective way to decrease the time period that drugs can be detected in your system. Physical activity can increase your metabolic rate as much as two thousand percent! Nothing beats proper training taken to an extreme. A high calorie diet is the next best way to increase metabolism. Consuming mass quantities of high calorie food will increase metabolic rate by up to 10 percent. On the contrary, a malnutritious (light) diet could lower your metabolism by 10 percent. Speed (the drug) will also increase metabolism. Unfortunately, labs usually test for speed, and could get you into trouble. So exercise with intensity, and eat big.