Tips for Passing a Cannabis-Detecting Urine Test

Tips for Passing a Cannabis-Detecting Urine Test

Although cannabis testing can be done on blood, sweat, saliva and hair, the least expensive and most common is urinalysis, which is used for about 90 percent of workplace-initiated drug testing.

The enzyme multiplied immunoassay technique (EMIT) detects THC-COOH, a marijuana metabolite that is fat soluble (stored in the fat cells) and therefore exits the body slowly. The metabolite can have an elimination half-life of up to 13 days, although infrequent cannabis users have tested “clean” within several days of last use. For regular users, the metabolite can be found in a standard urine screen for days and sometimes weeks. EMIT generally detects THC-COOH at levels of 50 ng/ml or higher.


The most successful way to pass a drug test, of course, is to abstain from tested substances. But knowing how long to refrain has been a source of debate since drug testing became a workplace standard.

Generally, the abstinence recommendations for cannabis are: 

  • Casual User (Several times a month): Four days to one week
  • Regular User (Daily): Two to three weeks
  • Heavy User (Multiple times daily): At least one month, with some users testing positive for months after last use

Note: People with high body-fat ratios retain higher levels of fat-soluble THC-COOH and will fall on the longer end of the suggested abstinence period.


The next best option to pass a marijuana urine screen is to drink copious amounts of water immediately before testing the urine. This process doesn’t actually flush metabolites from your system; it essentially dilutes the urine sample enough to drop THC-COOH below detectible levels.

  • Three days before your test, begin taking a creatine supplement (available in health stores) or eat a lot of red meat to build your levels. Drug-testing contractors look for abnormally low creatine levels as an indicator that dilution tactics have been employed.
  • An hour or two before your test, take a B-complex vitamin supplement (B-2 or B-12), which will add a yellow color to your urine (50 – 100 mg). Urine that is too clear is a visual indicator of dilution.
  • Beginning two- to three-hours before your test, drink 12 – 16 ounces of water every 15 minutes. Don’t glug---too much water can lead to water intoxication. A diuretic, like cranberry juice, herbal tea, or caffeine can also increase urine production.
  • Urinate at least once during the dilution process – you do not want to submit the first “flushed” urine for testing, especially first morning urine, which tends to have higher levels of metabolites built up during sleep. Some people recommend “stream interruption;” starting to urinate in the toilet and then switching to the collection container.
  • Take four 325-mg aspirin four-six hours before your test. Aspirin (acetylsalicylic acid only, not other pain relievers like Advil or Tylenol) interferes with EMIT drug screening by masking certain parts of the spectrum that urine testing checks.

Sample Substitution

Many people report successful methods of substituting clean urine for screening tests, but a great deal depends on the procedures employed by the drug test facility. Many sites prohibit test subjects from washing hands (so no dilution is possible), put dye in the toilet water, pat down subjects prior to testing or have a technician observe the collection process. If you are permitted to enter the test room fully clothed and without observation, these methods may work for you:   Urine belts which, when worn close to the body, keep the sample at body; temperature, provide a pouch for the sample and tubes for streaming;

  • A shoe pouch that conceals an un-lubricated condom containing urine and a pin (to pierce the condom) hidden in a trouser fly;
  • Securing a urine-filled condom to one’s genitals;
  • Freezing “clean” personal samples and then warming and transporting, and
  • Synthetic Urine Kits which are mixed ahead and kept at body temperature and transported in the above ways, among others
  • Critical in the success of the substitution method are two things: 

Critical in the success of the substitution method are two thigs:

  1. Taking the sample into the testing room must not be observed by staff.
  2. The provided sample must be body temperature.


Essentially a delay tactic, some people choose to contaminate a urine sample with soap, saline drops or bleach to invalidate a test. Most testing facilities screen for these substances and the sample is tagged as adulterated. Although not an end solution, it can give a person time to fully detox before retesting.

Detox Kits

There are hundreds of “detox kits” and beverages on the market that offer questionable results. Some theorize that these elixirs contain the same ingredients you can assemble yourself in a dilution protocol (Vitamin B, Creatine and Aspirin) accompanied by a lot of water.


If you opt to try one of these protocols, it is highly recommended that you execute a test run prior to taking a mandated urinalysis. Test strips that measure THC-COOH in urine are widely available and reasonably priced.