Diluted Drug Test Results and How To Prevent It?

Diluted Drug Test Results and How To Prevent It?


Dilution in the drug test sample is becoming prevalent nowadays. A diluted sample contains more water than other essential elements in the specimen.

This may happen accidentally sometimes as the individual would have consumed more amounts of water before producing the urine specimen. Nevertheless, there are cases where the dilution is intentionally done by the candidate to surpass the drug test.

Every specimen has a certain cut-off level to reach its validity. If the drug level in the specimen fails to reach such a cut-off point, then it is considered as negative even if the specimen contains the drug traces in it.

It is because the amounts of drug traces present in the urine specimen is not greater than or equal to the predetermined cut-off level. Hence, this signifies that if there are minimal amounts of drug traces in the urine specimen, it is considered to be negative drug test.

In this blog, we are going to discover the causes of diluted drug tests and how to prevent dilution of specimens.

Table of Contents:

What Causes Diluted Drug Test Specimen?

There are several reasons behind the dilution of the drug test specimen. The specimen would not seem to be diluted when it is handed to the tester. It is only found out later due to the lack of certain elements present in the urine sample. A urine sample without essential elements would not produce effective results. Hence, the tester will ask the donor to provide another sample if the earlier provided sample was found to be diluted.

Urine sample dilution may be done intentionally or unintentionally. First, we will explore how unintentional factors can lead to the dilution of the urine drug test sample.

Unintentional Factors

  1. Consuming Plenty Amounts of Fluids:  Some people would love to stay hydrated. Even their normal urine would not be pale yellow. It is because they would have taken more water or fluid-containing foods than solid foods. When these kinds of people are tested, they produce dilute urine as they are used to such routines. In that case, the tester will ask the candidate to alter the consumption of fluids in order to make the urine efficient enough to test for drugs.
  2. Preparation to Produce the Urine Sample:  Some people, on the contrary, do not consume more fluids and drink water less than the normal amount. These people would find it difficult to produce enough urine during the drug test. The tester would instruct these candidates to drink more amounts of water. In such cases, people tend to drink large amounts of water, which may lead to the dilution of samples.
  3. This can happen due to certain reasons. When the tester identifies less amount of urine and instructs accordingly, the candidate will become tense or nervous and drink more amounts of water. This will lead to frequent urination. Psychologically, the candidate will ensure whether the urine is diluted or not by doing certain self-checks and then further drink more amounts of water. Then the donor collects the urine and gives it to the tester. This will have more chances of getting diluted.
  4. Diuretics:  Diuretics are usually prescribed to people for certain medical conditions that can change the hydration level in the body. This is also prescribed to patients who have high blood pressure and edema. Commonly called water pills, these diuretics will help to eliminate the salts and other unessential elements from the body through urine and bowel movements. Certain diuretics including thiazides have a greater impact on the hydration and urination frequency of the people.
    Hence, candidates taking diuretics will show diluted urine in the test results. Apart from that, certain energy beverages like tea and coffee are also considered diuretics. People consuming more tea and coffee will also have greater chances of developing diluted urine samples.
  5. Kidney Failure:  This is also one of the major factors that lead to the dilution of the urine sample. The function of the kidneys is to filter out all the impurities in the body and water, and flush them out in the form of urine. This urine will contain urea and creatinine as major elements. During kidney failure, it absorbs the solute, but cannot absorb water. Rather, it releases it as urine without any impurities.

Intentional Factors

The intentional factors are those that lead to dilution with the knowledge of the candidate to evade detection of any drugs during the drug screening process. Some of the intentional factors are:

  1. Intentional Water Intake:  This is one of the common causes for dilution among the drug testing candidates, especially among the probation drug test population. Drinking more amounts of water a week before the drug test will dilute the drug traces and also the essential cut-off elements in the urine sample.
  2. Taking Falsified Prescriptions:  Many people go further to take some falsified prescriptions like thiazides claiming that they have high blood pressure. This will not only dehydrate your body, but also make it still worse and can even lead to undeniable consequences.
  3. Injecting Creatine:  Intentional users use this injection to tamper with the urine drug test more intelligently. Yes, they take creatine injections or tablets after diluting the urine to the maximum. This creatine will enhance the creatinine artificially in the urine sample during the drug test. However, the fact is that the tester will easily identify the tampering if creatinine level is remarkably high or lower than the normal range.
  4. Mixing Water or Replacing the Sample:  This is also one of the most common methods followed to tamper with the urine drug test. Some candidates add clear water to the urine to dilute it or use synthetic urine. This could be easily identified by the tester by analyzing the external texture itself.

To some extent, candidates even will try to replace their urine sample with other normal person’s urine. With this technique, the donor may clear the initial level drug test, but consecutive tests for confirmation will display the fraudulent practice. This will attract jail terms.

Despite these factors, the laboratories today have advanced themselves to identify the fraudulent practices that the candidates attempt to pass the drug test. Let us explore the precautionary and action measures followed by the labs to detect the dilution of the drug sample.

How Do Labs Detect The Diluted Drug Test Results?

Labs do follow certain methodologies to find out the cheating done by the users to pass the drug test. It involves technical and non-technical falsified sample submission.

In the technical aspect, the testers use two major techniques - The urea-creatinine test and the specific gravity test.

Urea-Creatinine Test

Urea and creatinine are the two major elements flushed out from the kidneys. The kidneys gather the creatinine generated by our body muscles, separates the element from the blood and sends them out of the body along with urine. A normal person’s creatinine will be within the normal limits. If a donor has consumed more amounts of water, the presence of creatinine in the sample will be less. If the creatinine is remarkably higher, then the sample may be adulterated.

There is another such case where the creatine injections or creatine tablets would be taken by the candidates. In such instances, the tester will easily discover the presence of more than normal amounts of creatinine in the body and flag the specimen.

The amount of creatine present in the body depends upon the body mass. To be more specific, a normal person will have creatinine in the range between 20 to 400 milligrams per deciliter. If the urine is diluted, then the creatinine ranges from 2 to 20 mg/dL.

Specific Gravity Test

This is another such prominent method to identify the diluted drug tests. Specific gravity is helpful to identify the concentration of the urine specimen. It compares the drug test specimen with that of normal water and identifies the absence of essential elements in the urine specimen.

For a normal person, the urine specific gravity ranges from 1.002 to 1.030. If the sample is diluted, then the specific gravity ranges from 1.001 to 1.020. Any sample that does not satisfy the specific gravity is considered as diluted.

Laboratories test for dilution in urine drug test because it is difficult to trace the drug presence in the sample. Only the essential substances in the urine will hold the drug traces. If it is absent, then there is no way that the tester will determine the drug metabolites. It is of more concern nowadays as diluted drug testing is becoming a serious problem.

Diluted Drug Test Results Are Such A Problem - Why?

Dilution will not provide any conclusive results regarding the drug use. The tester may conclude it positive or negative for drugs based on the results on those diluted samples. There are two ways that the tester will determine based on those diluted ones. First, if the diluted sample tested positive for drugs, then the tester will conclude it positive no matter whether it is diluted or not.

However, if the diluted test specimen is tested negative, the tester will not come to an immediate conclusion since there may be other possibilities for the sample to get diluted, including:

  • The candidate could have consumed more amounts of water without knowledge and this could have led to specimen dilution. In that case, the tester will provide certain instructions to the candidate regarding the fluid intake and schedule another drug test.
  • If the candidate had intentionally done the dilution and successfully masked the drug traces, the tester would not conclude this as negative. In this case, the tester will recommend a second drug test. Again if the second urine specimen is found diluted, then it will be considered as a positive result for drugs.

How To Prevent Dilution While Doing Drug Testing?

Be it accidental or incidental dilution, it is always an embarrassment for both tester and the candidate if the sample is diluted. So, it is best to prevent the dilution of drug samples using certain techniques.

  1. The lab should randomly fix the drug test so that the candidates will not have a chance to dilute their samples.
  2. The sample collection should be time monitored so that the participants will not engage in any alternate practices to pass the drug test.
  3. The candidates should be given instructions on the amount of water and other fluid consumption to prevent dilution of the sample.
  4. No diuretics including coffee or tea should be taken by the candidate before the drug test.
  5. The labs should try to schedule drug tests as early as possible in the morning. This is because the early morning urine will be more concentrated.
  6. To prevent the illegitimate addition of water to the sample, the labs should block all the water supply as well as add blue dyes to the toilet water. This will make it impossible for the candidates to dilute the sample intentionally.
  7. The labs should prevent the candidates from carrying any bags or any other personal items during sample collection. The donors may bring adulterants in order to dilute the sample. Hence, bringing in any personal stuff should be strictly prohibited in the collection area.

These are some steps that the drug testing labs can follow during the sample collection. The testing labs use high-end equipment to test the presence of drug and dilution is one such concern.

At present, the drug test is conducted utilizing two ways - Immunoassay and Gas chromatography. Immunoassay is used for preliminary testing whereas the latter is widely used for confirmatory purposes as it produces accurate results, but it is expensive. Testing of diluted samples will be a waste of time. Hence, the above techniques can help prevent specimen dilution to some extent.

Final Words

Diluted urine is one such concern when it comes to urine tests for drugs. It does not mean that all of them taking up the drug test are trying to cheat. It might happen casually due to the consumption of more amounts of fluids. This can happen if people take diuretics for medical conditions or due to kidney problems. It is in the best interest of the laboratories to take necessary steps to prevent dilution by using precautionary methods and techniques. With the increasing demand for drug tests in almost all the industries, it is the most crucial step that the labs should consider to limit the dilution of the sample.

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