Adulterating involves adding a substance to a urine sample that prevents a positive test result. This is also a high risk technique that requires very careful preparation.


The adulterant that is used most often in drug tests is probably salt. You don't need to use a lot of salt. It works particularly well when an EMIT drug test is used. Adding a small amount of regular table salt, lye or ammonia serves to neutralize enzyme activity in the sample which ensures that the sample has a "no drug content" result.

You are unlikely to succeed in using salt for a confirmatory drug test which uses more accurate and sensitive methodologies. Thin-layer chromatographic (TLC) test results will not be affected if salt is added to the sample. Drug test manufacturers often explicitly warn employers about the possibility that salt can be used as an adulterant and they may advise that the testing also include a test of the pH level of the urine samples. Some of the common adulterants will raise the sample's pH above the regular level for urine. If the company suspects that you have tampered with your urine sample, then you are likely to be interrogated and viewed as more suspicious. The second test will probably be under direct observation.

Getting Adulterants into the Test

Some people have succeeded in getting salt and other adulterants into the testing room under the fingernails or on their hands. This doesn't work in tests that are being administered according to the Federal Guidelines as they require hand to be washed and nails scrubbed in front of the test monitor. If the test doesn't follow the Federal Guidelines then you may get away with hiding salt under your fingernails, however there can still be problems in ensuring that the salt works properly.

When putting salt into the urine sample you need to be absolutely sure that there are no undissolved crystals in the sample cup as this is an obvious sign that the sample has been adulterated. Furthermore, carrying salt in your pockets may be discovered as drug tests will often involve asking the employees to open each of their pockets before entering.

Other Popular Adulterants

In the book "Conquering the Urine Test", Nightbyrd outlines other adulterants that can be used in drug tests, including ammonia (1 capful) and bleach (2 tablespoons). Adulterating a urine sample with ammonia is not advised as the strong smell will give it away. Liquid bleach works by destroying traces of cannabinoids (including THC) in a urine sample. Avoid bleaches that contain blue dots because they will make the adulteration obvious to see. You could also use odorless hydrogen peroxide. This generates a chemical reaction that will alter the urine in such a way as to produce a negative drug test result.

Adding Liquid Drano has also been proven to produce a false negative when urine is tested for marijuana, opiates, cocaine, amphetamines and barbiturates. Be careful though because it will bubble and fizz when added to urine and this can reveal the adulteration. Another problem with using Drano is that it raises the pH of the urine to unrealistically high levels. Vinegar is also frequently used to adulterate urine samples and it can be effective in removing traces of marijuana from a urine sample.


An article published in "Clinical Chemistry" revealed that adding 2 drops of liquid soap is sufficient for making the results of an EMIT test negative. This is also a very easy adulterant to add if your drug test collection takes place in your own bathroom (as insurance policy test frequently are) or your doctor's office. The important thing to avoid is the presence of soap bubbles in the urine sample!

Byrd Laboratories sell an additive called "UrinAid" that is designed to help you pass marijuana test using the EMIT method. This product is very effective in removing traces of THC and other drug metabolites. The only issue with using this product is that the government now knows about it and will often test specifically for its presence in a urine sample.


Blood is also an adulterant in urine samples. If, for example, you happen to prick your finger in the process of giving a urine sample and a few drops of blood fall into the sample, it may produce a negative result when tested for cannabis. This has been stated to be true by the Medical Professor and Director of Pharmacology at the New York City University, Dr John Morgan. Drug tests will often use blood samples in order to show the present level of intoxication, but the presence of just a few drops in 60ml of urine will not be enough to create a positive test result. The effectiveness of blood as an adulterant was tested and denied by Byrd Laboratories. Byrd Lab also tested the following adulterants and found them to be ineffective: test Free, goldenseal, Visine and Nature Klean.


Using some substances (such as juice, vinegar or Drano) as adulterants in a urine sample can result in a large change in the pH of the urine. This is obvious to the tested and they will generally report these cases to the employer. Human urine samples have a fairly narrow pH range from 4.5 to 8.5.

You are more likely to get away with adulteration in an EMIT or other type of screening method, provided that you don't get caught adding the substance or the urine sample doesn't present another obvious sign, such as an incorrect temperature or blue dots from a bleach adulterant.

Amounts of Adulterants needed for EMIT Tests

Adulterant Amount Needed
Salt 1/2 teaspoon per 10ml of urine
Vinegar 5 drops per 7-10ml of urine
Bleach 1 drop per 5-10ml of urine
Liquid Soap 1 drop per 5ml of urine
Liquid Detergent 1 drop per 5-10ml of urine
Blood 1 drop per 5-10ml of urine

It is possible to detect some adulterants (such as Drano, ammonia and bleach) when specific gravity, creatinine or pH tests are conducted on the urine sample. In reality, drug programs rarely bother with these tests because they are expense and timely. Any adulteration of urine samples will definitely be revealed if the sample is tested using gas chromatography / mass spectrometry (GC/MS). This is another reason why you should find about as much as possible about the tests that are being conducted before you adulterate your urine sample in any way.

Don't be Silly

In the preceding chapters we have covered several possible solutions to the issue how to pass a drug test. These are the ways that you could go about trying to "rig" drug test results (dilution, substitution and adulteration). All of these methods are very risky if you are discovered. If you get caught using these methods, it will generally be assumed that you are a drug user with something to hide. Moreover, you need to have an extremely detailed understanding of the procedures and technology that your drug test will involve in advance in order to have any chance of getting away with these methods. Trying as hard as you can to flush out your system will not necessarily assure a negative drug test result. The best strategy for anyone faced with a possible drug test who really wants to not get fired is obviously abstaining from taking any drugs at all. employers are regularly assured by the drug testing companies that they will catch anyone attempting to cheat on the tests. They continuously monitor the products designed to beat a drug test and find ways to stay ahead of them.

The States are also becoming more involved in preventing tampering with drug tests. Nebraska and Texas both now have laws that make falsifying a drug test a criminal offence. In 1998 Pennsylvania also passed a law to criminalize the sale, sharing or use of clean urine designed to help people pass drug tests.