What happens if urine sample is too diluted?
Diluted urine occurs when there's too much water in the urine. It means the urine's concentration is weak. As a result, the tester will be unable to properly detect the presence of drugs in the urine.
There are two types of dilute specimens: positive and negative. With a positive diluted drug test, the laboratory picks up the presence of an illegal substance despite its dilution. Whether intentional or accidental, the dilution didn't hide the drug levels.
The U.S. Department of Transportation allows a regulated employer to accept a negative-dilute specimen as negative, and many companies (DOT-regulated or not) choose to accept them. As a result, many substance abusers get hired.
When a urine specimen is “dilute”, it is possible that drugs in their system may not be detected. Don't be alarmed if your employer tells you the drug test result is a negative dilute result. This should never be a reason for you to be terminated or not get the job.
Note: A negative dilute is not a violation, it is a negative drug test result. There should be no violation consequences for a negative dilute drug test result. It is a negative result but could potentially be suspicious because of the amount of water in the urine.
When a drug test comes back as a negative dilute, it basically means that there was too much water in the urine to get an accurate screening. The creatinine concentration in the urine sample is the primary measurement for identifying dilution, and if the sample contains no creatinine, it can't be counted as urine.
Even though a urine sample is diluted, chances are excellent that there will still be enough of a tested drug or its metabolites in the sample to produce a positive result. If a sample is too diluted and the results are negative, the employer may send the employee back for additional testing.
Another potential cause of a false pregnancy test is if the urine used for testing is too diluted. If the urine is not concentrated enough, then there may not be enough hCG in it for the test to detect. Because of this, Dr. Price recommends not drinking any liquids for a couple of hours before taking a pregnancy test.
Depending on a company's policy, employers may retest the donor if it is dilute. However, if the specimen is extremely dilute (creatinine of 2-5mg/dl) the employer must retest under direct observation4.
For negative dilute drug test results, there may be an option to retest, depending on what's stipulated in the company policy. In such a case, the drug testing center may require that a new sample be submitted— this time, having the client avoid drinking too much water beforehand.
What color is diluted urine?
The intensity of the color usually varies with urine concentration; thus, concentrated urine is dark yellow, and dilute urine is pale yellow.
If the specimen has a creatinine of more than 5 mg/dL or less than 20 g/dL, and a specific gravity of less than 1.0010 or greater than 1.0200, it's considered a dilute specimen.

Drinking large volumes of just about any non-toxic water-based liquid will dilute urine. Drinking two or three 12-ounce glasses of water at the same time can produce 10-fold diluted urine within only half an hour and the dilution effect may last for hours.
Avoid all diuretics-including caffeine-the day of the selection until AFTER the collection is done. Go to the collection site while the first morning urine is still in your bladder to use this as the specimen.
The only thing that affects a dilute sample is the amount of fluid taken in within a short period of time prior to providing the urine sample. If you are seeing results that show you are getting close to a dilute sample, try to stop drinking any fluids 2-4 hours prior to providing the sample.
There are other reasons your sample may not contain detectable levels of bacteria, including over-hydration. If your bladder is frequently flushed and your urine is diluted, your sample may not contain enough of anything a urine culture can detect.
The normal level of creatinine in urine ranges from 60 mg/dL to 300 mg/dL. A dilute urine sample means that the creatinine level is equal to or below 20 mg/dL. This also occurs normally in the absence of kidney disease.
If the second specimen test result is also returned as dilute, then that is considered a final result and no further tests are performed. The second negative dilute is accepted as a negative test result.
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