What Is an Accidental Dilution Drug Test

At one point or another, employers of truck drivers who are completing required drug testing may have encountered a test result that differs from the standard “positive” or “negative” result—dilute specimen. 

That's why most trucking companies find it more convenient and practical to be part of a Consortium/Third-Party Administrators (C/TPAs) like Labworks USA to manage all, or part, of an employer's DOT drug and alcohol testing program. We perform tasks as agreed to by the employer to assist in implementing the drug and alcohol testing program and to help keep the employer compliant with the DOT/FMCSA Drug and Alcohol Testing rules and regulations. We as a DOT Consortium can help you.

Moving forward, what is an accidental dilution drug test, and how does the DOT instruct drivers and employers to handle such test results? Read on to find out.

What Is a Diluted Drug Test?

A diluted drug test is a test in which a urine sample contains a much higher percentage of water than a usual urine sample would. This higher percentage of water causes the other substances in the urine to be diluted, making it much harder to detect traces of drugs in the sample. A diluted drug test may return with one of two results: positive dilute or negative dilute. A positive dilute result means that despite the dilution of the sample, drugs were detected in it. A negative dilute result means that no drugs were detected in the diluted sample—but this does not necessarily mean that sample contained no drugs, as they may have been present but undetectable due to the dilution.

What Are Some Causes of Diluted Drug Tests?

Sometimes, a sample is diluted intentionally when the owner of the sample has been using drugs and wants to hide the evidence. However, it is occasionally the case that a person will accidentally dilute their sample, perhaps by drinking too much water prior to providing a sample. This would be a case of accidental dilution. Whether intentional or accidental, there are a few reasons that a sample could be diluted:

• Drinking more fluids than usual prior to providing a sample
• Adding water to a sample from an outside source
• Taking certain medications or having health conditions that may lead to diluted urine

DOT Policies on Dilute Drug Tests

The DOT has clear policies on how both positive and negative dilute drug test results should be treated. Because a positive dilute result means that drugs were detected in the sample, a positive dilute result should be treated like any other positive drug test result. A negative dilute result, on the other hand, is a bit more ambiguous. The DOT holds that negative dilute results may be accepted as a negative test result if an employer desires. However, an employer may also choose to require a retest for those with negative dilute test results to ensure the test truly was negative.

For your reference, here's a list of DOT Consortium services we offer at Labworks USA with respective rates.

Knowing what a dilute drug test result means and what an accidental dilution drug test is will help you know what to expect from these results as a driver or how to address the situation as an employer. If you suspect that one of your employees is intentionally diluting a drug test sample, you may want to administer another drug test and closely monitor any random drug tests they take. Labworks USA can aid you in DOT random drug and alcohol testing compliance by helping administer, monitor, and track these and other required drug tests for your employees.

Our DOT Consortium's friendly team will be more than happy to discuss any concerns you may have and work with you to ensure you are always fully compliant, especially with random DOT drug and alcohol testing and pre-employment testing. Moreover, if you need help with FMCSA Clearinghouse registration, we can further support you.