Urinalysis Adulteration/Specimen Validity Examination
Orbit Labs requires that each urine specimen be examined for signs of adulteration. This examination includes the following:
Physical Examination: Color, excessive foaming, excess sediments, or unusual odor are noted. If adulteration is suspected, this is noted on the final report.
Analytical Examination: pH, creatinine, oxidants and specific gravity are run to aid in determining specimen validity or possible adulteration.
Individuals being drug-tested and those responsible for urine testing programs are aware that specimens submitted for testing are vulnerable to adulteration (tampering). Although collection procedures are in place to ensure specimen integrity, donors have demonstrated ingenuity in their efforts to defeat the testing process. Possible methods of avoiding drug-use detection include the addition of adulterants to the specimen, the substitution of someone else’s urine and specimen dilution. Both specimen adulteration and specimen substitution are difficult to accomplish during an observed collection. The presence of adulterants in a urine specimen has the same implications as the presence of drugs. As a result, the most common way to mask drug use is by “internal” dilution (Flushing). This is done by excessive water consumption, and/or taking diuretics such as herbal teas.
Creatinine as an Indicator of Normal vs. Abnormal Urine Specimens
Creatinine is a naturally eliminated in the urine at a relatively stable rate. Therefore, the urine creatinine level indicates the urine concentration. Most normal urine samples will have a creatinine value between 20-350 mg/dL (milligrams per deciliter). A specimen with a urine creatinine level less than 20 mg/dL is considered “dilute”. Less than 2% of people normally produce a urine sample with a creatinine level under 20 mg/dL. Among those urine samples submitted for employment related drug testing, about 2% (slightly higher than normal) are dilute. Finally, 8% of those urine specimens submitted for court-directed drug tests have a creatinine level under 20 mg/dL.
Drugs are present in the urine in proportion to the urine concentration. When the urine is less concentrated, there is a lower concentration of drugs. When the urine is too dilute, a negative result does not assure non-drug use. We recommend that negative drug test results be disqualified when the specimen has a creatinine level less than 20 mg/dL. Conversely, a positive result on a dilute specimen would not be disqualified, because this indicates that the drug was in such high concentrations that it was detected even with a low urine concentration.
The most common way for a donor to produce a urine specimen with a creatinine level below 20 mg/dL is to drink large quantities of liquid and/or take diuretics prior to providing a specimen. Commercially available products that are marketed as aids in “beating the drug detection system,” such as Clean-Free, SafeTest, Naturally Clean Herbal Tea and Goldenseal, can be effective because they contain natural diuretics and encourage additional liquid consumption.
Some donors deliberately drink large quantities of fluids for medical reasons or because they think it is a healthy habit. If a donor consistently provides a dilute specimen they should be reminded that it is their responsibility to provide a specimen suitable for testing and failure to do so might be considered “Refusal to Test”. They should reduce their liquid consumption and limit their use of caffeine and herbal teas. Most people will comply unless they are attempting to mask their drug use.
The best way to minimize the percentage of dilute urine specimens is to use a random collection program. Unannounced specimen collection presents the donor with little time to prepare. Another good practice is to get a first morning “void” if possible, as this specimen often is more concentrated. People who dilute their urine by drinking large amounts of liquids cannot continue this practice indefinitely.