Last updated : May 12, 2025
Drug users have been trying to pass off diluted urine specimens since the earliest days of drug testing. Moreover, truth be told, it used to work. Drug users who were due to take a drug test could successfully tamper with results by consuming large quantities of water.
Drug testing has come a long way since the 80s though, so, that’s no longer the case.
The drug testing industry has become much more sophisticated. Advancements in technology brought changes to testing procedures. The drug testing process, now, includes measuring the creatinine levels in the urine. If the creatinine level falls below normal, the urine is diluted which, of course, indicates someone may have been trying to tamper with the test.
The level of deception
The term “diluted urine” is pretty self-explanatory.
The body excretes waste through urination, however, if someone increases their liquid intake too much before providing a urine sample, it throws things off-kilter. It can cause the urine pH level to measure close to neutral.
When this happens, it throws up an immediate red flag because employers—and lab techs alike—know that drug users attempt to falsify drug test results by diluting their urine specimens. Most likely, in hopes of either cleansing the body at a quicker rate—which doesn’t happen, oh, by the way—or masking their drug use with a diluted urine sample.
Despite what they might have been told or read online, that doesn’t work either.
Test results
Diluted drug tests are marked as incomplete and the corresponding explanation could result in job loss. That’s because some company policies handle diluted test results the same as a positive drug test. If that’s the case, the employee is immediately terminated.
Some are more lenient so it depends on whether the test is marked as a positive or negative dilute.
Negative dilute
Having the word negative attached to a drug test result should be considered a good thing, right? Not when it pertains to a diluted drug sample because even though the test shows no evidence of drug use, the low concentration of creatinine contained in the sample caused by excessive fluid intake made it impossible to establish a negative result with certainty. In other words, if drug metabolites are in the body, they may have not been detected.
A negative dilute result doesn’t always indicate that a drug user was trying to slip by undetected. It could have been purely accidental. People who suffer from shy bladder syndrome, for instance, have trouble urinating in public restrooms. They may have drunk a large quantity of water before the test hoping they could “go” when they arrived at the testing facility.
However, the added stress of providing a urine specimen for a company drug test could make it impossible for them to do so. Anyone suffering from this condition should tell their employer about it—and perhaps provide a doctor’s statement to back it up—before reporting for the test.
Unfortunately, the DOT requires every test subject who receives a negative dilute drug test result to retest—and it’s observed. If the second directly observed test result is negative dilute, disciplinary action is taken. The driver is no longer eligible for hire until they complete the return-to-duty process.
Many employers of the general workforce enforce a drug policy that resembles the DOT’s concerning a negative dilute drug test. However, retesting may or may not be included in the policy. Depending on company policy, the employee may be terminated immediately.
Positive dilute
We mentioned above that drug abusers often try to flush drugs from their system. Sometimes they buy products advertised to mask drug use. Some try drinking excessive amounts of water before a drug test diluting the urine.
A positive dilute normally indicates two things to an employer.
- There were drugs in the employee’s system at the time of the test.
- They more than likely attempted to falsify the test result.
There will be no retest. Unless they have incorporated a second chance into their policies and procedures, employees who test positive for drug use are let go immediately.
It could be the catalyst
Pointing someone in the direction of help while sharing a few kind words of hope for their future on what is sure to be a very dark day may be the inspiration they need to quit using drugs. Drug addicts often deny they have a problem—especially to themselves. When they lose their jobs because they tested positive for drugs, the realization may finally hit home.
Knowing someone truly cares about their well-being in that moment can go a long way toward giving them the glimmer of hope that they need to kick their substance abuse problem.
Throw them a lifeline.
