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What You May Not Have Realized About Urine Drug Screening


Donors typically take 1 of 3 approaches when attempting to adulterate urine drug screening results: 

  1. Internal Adulteration: ingestion of a substance to disguise the drugs in the system.
  2. External Adulteration: adding a substance to a urine sample after voiding. 
  3. Urine Substitution: substitution of one’s urine for someone else’s drug-free urine.

Internal adulteration is the most common cause of specimen dilution. Dilution increases the volume of urine produced, which results in a higher instance of specimens with drug levels below the cut-off. Ingesting large quantities of virtually any non-toxic, water-based liquid can result in dilute urine specimens. For example, drinking 3, 12-ounce glasses of water prior to sample collection can produce diluted urine samples within only ½ hour — and dilution may last for a number of hours. In most cases, this will lower the concentration of some drugs in the urine enough to produce a negative test result. 

At SureHire, we are committed to providing high-quality testing services that help employers minimize the risk of impairment-related incidents at their workplace. Our urine drug screening process is renowned for having some of the lowest dilution levels in the industry. 

We recently spoke to SureHire’s Manager, Occupational Testing Services, Kelsey Sunders, to learn more about SureHire’s urine drug screening protocols and to find out what makes SureHire stand out amongst other occupational health testing organizations. Here’s what she had to say. 


Q: What makes SureHire’s Urine Drug Screening Protocol more effective in producing lower dilution rates than other occupational testing providers?

“SureHire has implemented a comprehensive dilution mitigation strategy across our testing network, which involves capturing dilution on-site through the evaluation of specific gravity and creatinine levels within the provided urine specimen. By implementing an on-site catch, 99.5% of all samples sent to the laboratory are within normal concentration levels, which reduces the amount of re-tests required from “Negative Dilute” results. 

For specific gravity, the normal range is from 1.005–1.030. For Creatinine, the normal range is 50–200. Anything below the minimum value is considered too dilute to test. Dilute donors are required to provide additional samples every 15–30 minutes up to a maximum of 3 hours in an effort to reduce the water levels in their system and improve the concentration of the sample. Once the sample reaches “normal” concentration levels, SureHire can get an accurate picture of potential drug analytes within the specimen. This process is adopted for all NON-DOT urine express and lab-based testing services.” 

Q: Why is it important for employers to utilize a drug testing provider with dilution mitigation strategies?

“Employers implement worker drug and alcohol testing as a control measure to reduce substance use in the workplace; however, if the drug testing program isn’t capturing all methods of substitution or adulteration, the program is not nearly as effective resulting in increased risk for the employer. Using a provider that has modern methods to detect dilution will ensure your program remains effective and keeps your workplace safe from the risks associated with substance use.” 

Q: What are alternative testing methods that employers can adopt that reduces the risk for adulteration or substitution such as dilution?

“Urine testing is the primary testing method for employment-based testing; however, there are so many products and methods available these days to help a worker cheat their test. Adopting oral fluid testing is a great alternative testing method, which has very limited adulteration or substitution methods and will ensure accurate results with no wait time as a result of logs.” 

Myth Busters

Q: Will dilution guarantee a negative result?

“No. While dilution does assist with reducing the level of drugs and in many circumstances, it will not guarantee a negative result 100% of the time.”

Q: Will taking additional creatinine help?

“No. Taking additional creatinine will just turn one’s sample bright yellow but will not increase the concentration levels of the sample.” 

Q: What if someone just drinks a lot of water and they’re not intentionally trying to cheat? 

"Unfortunately, there is no way to differentiate between high liquid consumers and individuals who intentionally consume a significant amount of fluids with the intention of cheating. However, individuals who dilute for the wrong reasons are usually significantly more dilute than the high-liquid consumer, meaning it won't take nearly as long to concentrate their sample to the point of acceptability."

QUESTIONS? If you have any questions about our drug screening programs, need help creating a drug testing policy, or would like to implement a customized program that suits your specific company needs, contact us

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