Cheating a Drug Test




Adulteration of urine is defined as the deliberate tampering or manipulation of a urine specimen with the intention of altering the test results. In layman’s terms, this involves a situation of a person trying to cheat a drug test. This is a well-known industry occurrence. Urine sample adulteration can produce false negative results in drug tests, either by interfering with the screening test and/or destroying or masking drugs present in the sample. Sample adulteration is usually achieved by three main methods:

  • Substitution: Substituting the donor’s urine for another, drug-free urine sample. This can be done in a number of ways such as inserting urine-filled balloons/condoms into body cavities for concealment and to normalise the sample temperature. Some drug users will go to extraordinary lengths to cheat a drug test, and there are numerous products available (primarily online) for those who wish to do so.
  • Dilution: Dilution is primarily attempted by the donor drinking excessive quantities of water or herbal teas in the hope of sufficiently diluting any drugs present in the urine to avoid detection. Diuretics may also be used. Commercial products to facilitate dilution include Clean-Free, SafeTest, Naturally Clean Herbal Tea and Goldenseal.
  • Chemical adulterants: There are a number of commercially available ‘drug test cheat’ products, including ICA, Spike and Klear.

In clinical practice, the accepted method to test for dilution is to analyse levels of urinary creatinine, pH, and specific gravity. A sample that demonstrates values outside of internationally accepted normal values will in most cases be due to deliberate dilution. Chemical adulterants will be suspected if glutaraldehyde, nitrite and oxidants /pyridinium chlorochromate (PCC) are present in the urine, as these chemicals are not otherwise found in human urine.

Expected values/results


Creatinine: Creatinine is a waste product of creatine, an amino acid contained in muscle tissue and found in urine. In an attempt to ‘cheat’ a drug test, the donor may drink abnormally large quantities of water or herbal teas, or injest diuretics to try to flush any drugs from the body. They may also dilute their urine with tap water, for example, so that drugs may not be detected. Low levels of urinary creatinine may indicate diluted urine; the absence of creatinine indicates that the sample is not human urine.
Nitrites: Normal urine should contain no trace of nitrites. If nitrites are present in the urine sample, this generally indicates the presence of an adulterant. Nitrites are present in a number of commercially available drug test ‘cheat’ products, with the primary purpose to obliterate the major cannabinoid (marijuana) metabolite THC COOH.

pH: pH measures the acidity or alkalinity of a substance. Normal urine pH levels range from 4.0 to 9.0. A pH outside of this range is suspicious for sample adulteration.

Bleach/Oxidants/Pyridinium chlorochromate (PCC): Household bleach or other oxidants, including specifically designed commercially available preparations, are sometimes used in an attempt to ‘cheat’ a drug test by breaking down drug metabolites that may otherwise be present in the urine. Oxidants, bleach or PCC is not contained in normal human urine, therefore the presence of these substances will in most cases indicate urine adulteration.

Specific Gravity (SG): Specific gravity measures the ratio of the density of a substance in comparison with a reference sample. The normal range for urine specific gravity is from 1.003 to 1.030. Low specific gravity levels usually indicate a diluted or adulterated urine sample.

Glutaraldehyde: Some urine drug screens or adulteration test strips test for the presence of aldehydes, which are not usually present in human urine. Commercially available adulterants may contain glutaraldehyde which can cause false negative drug screen results. Glutaraldehyde disrupts the enzyme used in some immunoassay (urine drug screen) tests.

Combating urine adulteration

Urine adulteration for the purposes of cheating a drug test is well-known in this industry. Qualified drug screening technicians should be alert for signs of suspicious behaviour during the urine sample collection process. A second sample may be required of the donor should the first sample fall outside of the normal ranges specified on the adulteration panel, or should the donor’s behaviour raise the index of suspicion for attempted adulteration. Some company policies require that any repeat sample must be done in full view of the drug screening technician.

As the drug test ‘cheats’ become more prolific and more sophisticated, so too do the adulteration tests both at the point of collection and in the laboratory.