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Watering down the “Pot of Gold”: What you should KNOW about “Diluted” Urine Drug Tests

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Watering down the “Pot of Gold”: What you should KNOW about “Diluted” Urine Drug Tests



Have you ever received a drug test result that says “Negative Dilute”? If you have, I am sure you were confused about what it meant. Companies immediately face questions like: does the person tested have drugs in their system or not, how does your company policy handle this situation, and should they be tested again.

What is considered “dilution” in urine drug testing?

ebookdilute2Dilution is the process of reducing the concentration of drug or drug metabolites in the sample. This is accomplished by adding fluid to the sample or by drinking large amounts of fluid to dilute the specimen, called "internal dilution." If the amount of the natural substance creatinine in the urine is abnormally low, internal dilution may be the cause. Drug testing laboratories all routinely test samples to detect dilution.

A dilute specimen, by definition, is a urine specimen that has a creatinine of between 2mg/dL and 20 mg/dl and a specific gravity of 1.003 or less. These 2 tests are routinely performed on every urine sample that is tested at the lab. If the specimen meets the above two criteria, it is reported as a "Dilute specimen". When a urine specimen is "dilute" and negative, it is possible that drugs in their system may not have been detected.

There are 2 circumstances that may cause a dilute specimen. The first would be caused by an individual diluting the urine with water, or other liquid, by actually pouring it into the specimen at the time of collection.

The second method of obtaining a dilute specimen is by consuming too many liquids, especially liquids that contain diuretics, prior to collection (i.e. coffee, soda, medications). This may be inadvertent or may be on purpose on the part of the donor.

What “Dilution” is Not

Dilution should not be confused with “adulteration”. This is when chemical adulterants are directly added to a urine specimen. Many products intended for oral consumption and claiming to help "rid the body of toxins" are sold over the internet. Although these "body cleansing" products may claim to "rid the body of toxins" (a fancy way to say they help beat drug tests), they appear to be effective only because of the large amounts of water the user is instructed to consume along with the teas or powders.

Positive vs. Negative Diluted Specimen

drug testing stats ebookWhen the lab reports a specimen as dilute, there are certain levels of creatinine and specific gravity that determine that the specimen may be dilute.  In other words, the donor consumed a larger quantity of water before providing the urine specimen.

This may be normal as many folks drink a lot of water for health reasons or because of a fear of not being able to urinate at the time of the drug test specimen collection.  In contrast, this may be abnormal as perhaps the donor is drinking an excessive quantity of water in an attempt to cheat on the drug test.  Thus lies the “gray” area concerning specimens that are reported as dilute.

If the report from your Medical Review Officer (MRO) is “Positive Dilute”, the results is Positive and the company should follow policy for the Positive result.  The indication that the specimen was dilute may be interesting, but it is not relevant to the handling of the positive test result.

For “Negative Dilute” results, the first question to ask yourself is whether or not the testing program is a regulated program – Federal employees or DOT drug testing. So what do you do when the Medical Review Officer (MRO) interpreting the drug screen tells you the test is negative, but also dilute?

Read Part 2 Here: How To Avoid A Workplace Drug Test Result Of A False Positive Or A False Negative

CleanFleet Can Develop And Review Your Drug And Alcohol Policy

drug and alcohol policy review and developement

Do you have a company drug and alcohol policy yet? If so, when was the last time you reviewed your policy? CleanFleet can help you develop and review your company’s drug and alcohol policies. Call us today to arrange a consultation with our expert staff at 503-479-6082.

14 Mar, 16

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There are 22 comments. on "Watering down the “Pot of Gold”: What you should KNOW about “Diluted” Urine Drug Tests"


  • ***B*** says: posted on 28 Dec, 2017

    Is a diluted test sent off to lab for further testing only if its a positive dilute or are negative dilutes also sent. My employer said my test was sent to the lab for testing BC it was diluted…what does this mean everything I read only says the difference between positive and negative dilute not which one or if both under go more test

    • ***Brian Gray*** says: posted on 28 Dec, 2017

      What type of drug test was this? A rapid drug test doesn’t analyse dilution. All other urine tests are already being sent to the lab for testing in the first place. For the Dept of Transportation, and most non-DOT companies follow their guidelines… negative dilutes are considered not a positive drug test but gives the employer an opportunity to re-test with a new sample if they wish, not re-test the same sample because it is found diluted. If it was a positive dilute, it would be considered a positive drug test regardless.

  • ***Jake*** says: posted on 01 Feb, 2018

    How long does it take to get the results back from the lab?

    • ***Brian Gray*** says: posted on 13 Feb, 2018

      Usually between 48-96 hours. It used to be a little quicker, but some some added drugs being tested in most testing panels is slowing down the lab process with more positive tests and other things clogging their workflow.

  • ***willow salvitore*** says: posted on 28 Feb, 2018

    if your urine is sent to the lab if its negative i should get a response within two days or less ? or if positive will they prolong the inevitable and make it 4-6 days?

    • ***Brian Gray*** says: posted on 02 Mar, 2018

      In most cases, yes, this is what tends to happen with that timeline. I will mention that if the result is “non-negative” (not just positive) a lab will spend more time with the sample.

      Sometimes the process (getting the chain of custody, etc) between the lab and company might slow the process down, but usually this is not an issue.

  • ***Michele*** says: posted on 16 Mar, 2018

    Okay so I took a 10 panel urine drug test and it became negative dilute so they have me do a retest this morning and I didn’t do anything to flush my system out I did nothing different to try to cover it up and when I go pee still dilute what do I do

    • ***Brian Gray*** says: posted on 02 Apr, 2018

      If this happens, we usually recommend asking the employer for allowing a hair or saliva test with the same drugs being tested. Dilute could be a signal for someone trying to cheat, but if it is a negative dilute, the Federal DOT just considers it a negative drug test and don’t require a retest.

  • ***Lo*** says: posted on 26 Mar, 2018

    Okay, so if it comes back “Negative-dilute”, isn’t there other possible reason(s)? Like for instance, taking prescribed potassium-sparing medications? Is this even an option to show/explain to the (potential) employer?

    • ***Brian Gray*** says: posted on 02 Apr, 2018

      You are right, there are many reasons why the sample could be diluted. Really, a dilute just means the creatine levels are off, but this is not necessarily a bad thing. It could signal someone trying to cheat a test, but definitely not always the case. In fact, the Federal DOT considers a negative dilute as a negative test, and don’t force a retest.

  • ***Pinkdelight*** says: posted on 05 Apr, 2018

    So I took a urine test and they said they didn’t test it because it was diluted. There is no way for me to do that as they put blue pills in the toilet so are they saying I spit it in? Because we can’t take anything in with us so what exactly is he implying. I do drink a ton of water and am severely skinny so it really goes through me but they said they didn’t even test it! How can you say it’s anything if you didn’t even test it at all? You eyeballed it and made a decision?

    • ***Brian Gray*** says: posted on 05 Apr, 2018

      I think this is specifically a communication breakdown. A “dilute” is only give when the lab actually tests the sample. If the collector is not allowing your sample to be sent in, they believe the sample was “adulterated” or there was a “substitute”. The next step for DOT Federal regulations is the next sample must be done under direct observation. Otherwise, whatever your company policy is for these situations is what should happen next in these scenarios. Why they think it was adulterated could be for a variety of situations: smell, temperature, etc.

  • ***Jimmy*** says: posted on 31 May, 2018

    I gave a urine sample a couple days ago for a dot drug screen. It was four of us who each had to give a sample, when the collector saw my urine she said its kinda diluted, and i told her i had drank a bunch of water so i could have some urine for the drug screen out of four of us only my urine was observed as diluted at the time of collection. Its been two days now since the collection and the other three guys have received their results today but mine hasn’t came in yet. What could be the delay? Do dilute urine samples take longer to test than normal negative samples?

    • ***Brian Gray*** says: posted on 01 Jun, 2018

      There are a lot of reasons why one sample at the lab might take a little longer then others. Sometimes the lab is just trying to get the best sample possible to test. Maybe it’s a negative dilute and they are testing again. Other outside scenarios are possible to slow things down that we’ve seen when we send a sample in to the lab and had to wait. The test result should come back pretty quickly now for you as it usually takes 2-3 days for results.

  • ***Rich*** says: posted on 08 Sep, 2018

    I took a urine test the other day and the technician inspected it, I could see with my own eyes they none of the lines moved. He then took out some type of packet and sprinkled it in. It was like a sugar type packet, same size and the same looking type of ingredient. He then looked at the sample again and then finished up the labeling having me sign in a few spots. I have NEVER seen this before. WTF was he adding to my sample ?

    • ***Brian Gray*** says: posted on 10 Sep, 2018

      This does sound shady. Was this for a federal DOT drug (urine) test? Was it at a collection site or was it on your job site?

  • ***lisa*** says: posted on 18 Dec, 2018

    do they test a “diluted” sample with the initial cut off or both the initial and confirmation cut off for dot drug test?

    • ***Brian Gray*** says: posted on 18 Dec, 2018

      If the initial cutoffs are hit, the lab confirms at the confirmation cutoffs regardless if the sample is dilute.

  • ***Julio T*** says: posted on 28 Dec, 2018

    First, thank you for taking time out of your day to answer our questions Mr. Gray. You must understand how frustrating it is to be stressing out over if you drank a bit too much water or not, and being classified and treated as if everyone has the same exact metabolism……
    Second, what I am to understand after reading your responses is that if the result of your sample is negative-dilute there is no reason for them to send your sample for confirmation testing right? They only send it for further testing if it tested positive in initial testing regardless if it also was flagged as dilute or not?

    • ***Brian Gray*** says: posted on 31 Dec, 2018

      Simple answer: it depends on the company’s drug testing policy. Regardless of DOT (federal) or non-DOT testing, it is highly suspicious to have a negative-dilute with creatinine levels greater than or equal to 2 mg/dl but less than 5 mg/dl; Specific Gravity less than or equal to 1.0010. A medical review officer (MRO, for DOT testing) will report the results as negative-dilute with a possible recommendation that the donor go for a second collection under direct observation. It is not recommended that a non-regulated employer required direct observed collections unless there is a significant concern for safety relative to the tested group. So, a negative-dilute is not required to be re-tested by federal laws, however recommendations or company policies may dictate a re-test, observed or not observed.

  • ***Jeff*** says: posted on 29 Mar, 2019

    Hey Brian, I had a 5 panel drug test this morning for a pre employment job. About an hour before I drank a cup of coffee and about 3-4 cups of water. Would this be enough to cause a dilute specimen? Thanks

    • ***Brian Gray*** says: posted on 30 Mar, 2019

      There doesn’t seem to be a consensus on precisely how much water it takes to dilute a urine sample. Some suggest that eight glasses consumed within two hours of a drug test is enough to dilute it. Others put the number at 24 ounces. These are on the more modest side. On the other end of the spectrum are those saying that to be safe, a half a gallon to a full gallon would likely cause a diluted drug test result.


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