What Are Adulterants? 9 Common Examples and How to Check For Usage

What Are Adulterants in a Drug Test?

Adulterants, by definition, are substances that change or ‘adulterate’ another material. In the context of drug testing, adulterants work to change a sample as a means to manipulate the test results. In other words, these substances can turn a positive (dirty) result into a “false” negative (clean) one. 

Here are some common adulterants used to modify drug test results:

1. Water

The simplest and most accessible adulterant of all - Water can dilute a test sample. It can be added to the urine directly, or the individual can opt to drink a lot of water before producing a specimen.

Drinking an abnormal amount/extra fluid prior to a test may dilute the urine sample and therefore may cause a false negative (clean) test result. 

2. Vinegar

Vinegar is another adulterant that can alter many drug test results. According to research, it can produce false negative (clean) results for the following tests:

  • Opiates
  • Cannabinoids
  • Amphetamine
  • MDMA
  • Alprazolam
  • Diazepam

3. Lemon Juice

Like vinegar, lemon juice can produce “false” negative (clean) results for cannabinoids, amphetamines, MDMA, Alprazolam, and Diazepam drug tests. However, it cannot adulterate opiates and cocaine drug test specimens.

4. Citric Acid

Citric acid is an adulterant found in shampoos and laundry detergents. When added to a specimen, it can alter the result of an otherwise positive (dirty) cannabinoid test. 

5. Bleach

Laundry detergent contains bleach; an adulterant that can render a negative (clean) Tetrahydrocannabinol (THC) test. It does so by oxidizing and destroying THC metabolites, essentially eliminating their trace from the specimen. 

6. Nitrite

Similar to bleach, Nitrite can oxidize the sample, destroy THC metabolites, and deliver a false negative (clean) result. 

7. Pyridinium

Pyridinium is another adulterant that can alter THC and opiates drug test results. Similar to the substances above, it works to destroy the metabolites that are detected in a drug test. 

A urine sample tainted with pyridinium will yield an orangey or reddish color.

8. Creatinine

Creatine is a substance found in diuretics or water pills. They work to ‘flush’ the drugs away from the body, thus rendering a negative (clean) test. 

9. Glutaraldehyde

Glutaraldehyde is a colorless solution used to cleanse and disinfect contaminated medical equipment. While it has a pungent odor, it’s not noticeable in small amounts. Such are used to destroy drug testing enzymes, thus creating a false negative (clean) result.

Adulterant Strips: Combating False Negative Results

Although some people will try to use the adulterants above to falsify their drug tests, they may not go undetected. Such is the purpose of adulteration strips.

These strips help prevent false negative (clean) results by indicating the presence of the contaminants mentioned earlier. An adulteration strip can check for several things:

Urine Specimen pH

pH is a measure of how acidic or basic a specimen is. The normal urine pH range is 4.6 to 8.0, and values lower/higher than that typically indicate the presence of adulterants.

For example, bleach and nitrite are both bases and, as such, could make the urine pH higher (more basic/alkaline.)

The following contaminants, could make the urine pH lower (more acidic):

  • Vinegar
  • Lemon juice
  • Citric acid 
  • Glutaraldehyde
  • Pyridinium

Specific Gravity

Specific gravity or relative density measures the density of a particular substance against the density of water. As for the case of urine, its specific gravity range falls between 1.005 to 1.030.

A specific gravity lower than 1.005 suggests that it is diluted with water, which can yield a false negative (clean) result.


A urine specimen should have a temperature range of 90 – 1000F. A temperature lower or higher than that means that contaminants have been added to the sample.

A temperature strip affixed in Ütest’s 7 Drug Cup test kit can check for anomalies in urine specimen temperature.


Adulteration strips can detect the presence of oxidants such as bleach - substances that can render a urine sample unstable.

Masking Agents

Adulteration strips can quickly check for adulterants simply because they don’t usually exist in urine. They can instantly pick up on masking agents such as glutaraldehyde or nitrate.

Creatine Waste Product

Although creatinine does a great job at flushing drug metabolites away from the system, its work doesn’t go undetected. It produces waste products, which adulteration strips can pick up quickly. 

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