FOCUS ON DILUTES AND SUBSTITUTION

Dilution 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 less than 20 g/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 2 criteria, it is reported as a "Dilute specimen". When a urine specimen is "dilute", it is possible that drugs in their system may not be detected. We recommend that an employer have a section in their drug testing policy stating that another specimen be collected as soon as possible, this will help prevent false negative results. However, the employer may accept the negative results with the notation "dilute" from the lab. (Contact joe@drugtestingusa.com for assistance with drug testing policy development)

The DOT policy regarding negative-dilute specimens - The employer may require the donor to submit to another specimen collection. The re-collection cannot be done under direct observation. If the employer adopts a policy of re-collection for negative-dilute results, all employees must be treated the same. However, the employer may elect to treat different types of tests differently (e.g. re-collect for pre-employment tests, but not for random tests). If the second test is also negative-dilute, the employer must accept that result and cannot continue re-collections. The second test is the test of record. An applicant/employee's refusal to submit to a re-collection for a negative-dilute result is a refusal to test under the DOT rule. (See more on DOT below)

Dilution should not be confused with adulteration, where 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" (i.e. help beat the 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. Consumption of excess fluids is the most effective way to dramatically increase urine production rates and produce dilute urine specimens.

Substitution occurs when the donor switches his or her own urine sample for a drug-free specimen at some time during the collection process. Sometimes the donor may submit something other than urine. Test results are reported as "substituted" when samples do not contain certain chemical components characteristic of normal human urine. All samples are screened for parameters that indicate samples that are not human urine.

DOT Changes Rule on Drug Testing

On May 28, 2003, the Department of Transportation announced that it was immediately changing the definition of a "substituted" specimen in urine drug testing so that urine specimens with a creatinine level greater than 2mg/dL but less than 5 mg/dL will no longer be reported as "substituted." This change is important because a "substituted" test is considered a refusal to take a drug test, which is a violation of DOT rules equivalent to failing a drug test.

The reason for the change is that the DOT has learned of a small number of cases in which individuals appear to have had legitimate medical explanations for producing specimens with a creatinine level of less than or equal to 5 mg/dL. In addition, the DOT concluded that there is an increasing consensus among scientific and medical experts that the 5 mg/dL standard may not be appropriate.

Under the new rules, when the Medical Review Officer (MRO) gets a report from the laboratory that the creatinine level in a specimen is less than 2 mg/dL or the creatinine is "not detected," the MRO will report the specimen to the employer as "substituted."

When the MRO gets a report from the laboratory that the creatinine level in a specimen is greater than or equal to 2 mg/dL but less than or equal to 5 mg/dL, the MRO will report the specimen to the employer as "dilute" and must, under the new rules, direct the employer to require the employee to undergo an immediate recollection under direct observation. The employer must then ensure that this recollection takes place.

"Based on the our drug testing experience and recent scientific and medical information, we have concluded that we should change the way we treat highly dilute specimens," said Ken Edgell, Acting Director of the Department's Office of Drug and Alcohol Policy Compliance. "We want to take every precaution to ensure that a transportation employee cannot be charged unfairly with having substituted some other substance for his or her urine specimen."

For non-DOT testing programs one way to consider dealing with these issues is to eliminate them all together by implementing an oral fluid-testing program.

In partnership with several leading lab partners, OraSure Technologies markets Intercept®, the first laboratory-based oral fluid drug test. The Intercept® test serves the workplace, criminal justice and drug rehabilitation treatment markets. Benefits include simplified collection, faster results, cost savings, and minimized risk of adulteration.

For more information, please visit www.4intercept.com or call Florida Drug Screening at 1-888-441-4599 to receive pricing information or set up an account.