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Common Methods of Evading Accurate Drug Tests Results

First Check® Home Drug Tests are highly accurate in detecting drug use but can only work effectively when the urine samples they test have not been tampered with or the person taking the test has not purposely attempted to evade a positive test result. There are several common methods that are used to avoid positive detection on a urine drug test. Of course, the only way to guarantee that a drug test will be negative is to not use any illicit substances.

Below are the four most common methods used to evade a urine drug test.


  • When a tester drinks large amounts of water (at least one gallon) before taking a drug test, urine becomes diluted and metabolites from drugs may become undetectable.
  • If the first round of results is inconclusive and a second test is necessary, more time will have passed and detectable quantities of drugs may have naturally passed through the system.
  • Other methods for diluting the urine include adding a drop of water to the sample. However, whether it has been ingested or added to a sample, water can make urine look extremely pale and may raise red flags indicating that the sample has been tampered with.

Cleansing Products

  • There are an increasing number of products sold that claim to “cleanse the body of toxins” and specifically claim to mask illicit drugs in the system.
  • These formulated “detox” drinks are sold at local nutritional supplement stores and are widely available online.
  • They contain ingredients such as filtered water, fructose, maltodextrin, citric acid, potassium citrate, potassium benzoate, ascorbic acid, red 40, riboflavin, and more.
  • They work by masking the drug metabolites found in the urine. There is often a limited amount of time that these products can effectively conceal drug use (i.e., 3 to 4 hours)

Chemical Adulterants

  • Some of the most common agents that are added to a urine sample include bleach, eyedrops, hand soap, vinegar, table salt, and lemon juice.
  • These chemicals can be easily concealed in small vials and are usually added to the sample when individuals are taking the test unsupervised.

Synthetic Urine

  • Another common method for concealing drug use is to substitute “clean” urine that does not have any trace of illicit drugs for the urine that does contain drug metabolites.
  • This can be accomplished by asking a friend for a clean sample or by purchasing a clean sample online. (The clean urine is usually refrigerated and the temperature is a clear sign that the sample is not valid.)