Illegal drug abuse remains a significant public health problem. According to recent studies on health and drug abuse, more or less 25 million Americans ages 12 and up are currently using illegal drugs, a staggering 9.4% of the total population of the United States.
Cannabis was one of the most commonly abused illegal drugs, followed closely by cocaine, heroin, and lastly, hallucinogens. Government guidelines define a viable specimen as a urine sample containing substances that are not normal constituents or materials at a concentration that are not normal biological concentration.
Screening programs for pre-employment usually do not involve direct supervision of test sample that was collected from the subject; that is why applicants may attempt to deceive the drug screening by contaminating the sample. That is why it is essential for laboratories and clinics to recognize pre-analytically the diluted sample.
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How to cheat a drug screening?
Traditionally, people try to cheat a drug screen by these methods: substituting the urine sample with a fake or synthetic pee or a clean urine bought from a trusted source; drinking detoxifying products available in the market today to remove any traces of illegal substances; or adding adulterants in vitro to the sample after the collection.
Fake pee is very difficult to detect because these products have the same creatinine, pH level as well as specific gravity to real pee. Certain tests are needed to recognize components that are normal to the human urine, but is not found in fake ones like cortisol.
Commercially sold products available in the market that adulterate pee or flush out traces of illegal drugs can be classified under two categories. The first category includes tablets or fluids that dilute the urine by drinking a lot of water. Popular products available in the market today are Fast Flush Capsules, Absolute Carbo Drinks, Clean Gel Capsules and Absolute Detox drink.
The second categories are products consist of in vitro adulterants that are added to the sample urine after they are collected from the subject. Example of these products is peroxide and peroxidase-based Stealth, nitrate-based Klear, glutaraldehyde based clean add-it-ive and pyridinium chlorochromate or PCC based Urine Luck.
Not only that, iodine is a powerful oxidizing agent and can potentially destroy illegal substance, especially cannabis metabolites. According to research, papain with intrinsic ester hydrolysis ability can reduce the concentration of THC-COOH or tetrahydrocannabinol dramatically. Tetrahydrocannabinol is a metabolite of cannabis if it is added to the sample urine in vitro.
Click here to know more about THC-COOH.
Common household chemicals that are used as urinary adulterants
Individuals that are subjected to drug screening who wants to cheat their way to pass the test with flying colors may try to contaminate the sample using common household chemicals. But a lot of these chemicals can be detected using a specimen integrity screening. Both laboratories and collection centers have different methods to identify a potential invalid sample.
For example, the temperature needs to be within 90.5°F to 98.9°F. The specific gravity of the sample needs to be within the range of 1.005 to 1.030. The pH level should be at the range of 4.0 and 10.0. And lastly, the creatinine concentration needs to be in the field of 20 to 400 mg/dL.
But some drug screening laboratories consider creatinine concentration of 15 mg/dL as the ending cuts off. One common contaminant, sodium chloride, always provides a specific gravity of 1,035 and above if it is added at a concentration required to produce a false-negative test result. The bad news is, sample integrity screening does not detect all contaminants.
Detoxifying agents, diuretics and flushing
Detoxifying agents and flushing are usually advertised as an effective way to pass a drug screening. A lot of these products contain caffeine or other known diuretics to maximize the output of the sample urine, as well as artificial or natural flavoring agents and sugar. The goal is to produce a recommended cutoff confrontation.
Experts evaluated the effect of drinking a lot of fluids when it comes to false-negative cannabis and cocaine urine screening results by studying the ability of known detox liquids like hydrochlorothiazide or goldenseal root to cause false-negative test results.
Test subjects drunk more or less a gallon of herbal tea, water or take hydrochlorothiazide 23 hours after ingesting cannabis or using cocaine. The subject’s creatinine level dropped below the two-hour cutoff after drinking a lot of fluid.
Cocaine and cannabis metabolite levels, which is measured by EMIT or enzyme multiplied immunoassay technique and FPIA or fluorescence polarization immunoassay decreased dramatically and usually switched from positive to negative in individuals after drinking two quarts of fluid.
Even the excess water was very effective in diluting the sample urine to cause false-negative test results, although liquids like herbal teas can dilute the urine a lot faster compared to normal water.
To find out more about EMIT, you can visit https://en.wikipedia.org/wiki/Enzyme_multiplied_immunoassay_technique.
Testing urine sample for contaminants
Specially made urine dipsticks can be used to recognize contaminants in the pee. Most of these dipsticks can detect oxidants, creatinine, glutaraldehyde, nitrite, chromate or pH. Guidelines from the government agencies that focus on mental health and substance abuse require additional screening for urine samples with abnormal physical characteristics or samples that shows characteristic of contaminated samples during the initial test or confirmatory testing.
A pH level that is less than three or more than eleven, nitrate colorimetric or general oxidant screening needs to be performed to identify the nitrates in the sample.
It is crucial for screening centers and laboratories to detect contaminated samples in the pre-analytical step since there are a lot of contaminants that can invalidate immunoassay tests. Although specimen integrity screening can detect most household contaminants except eye drops and isopropanol or alcohol, contaminants that contain a potent oxidizing agent like potassium nitrite requires a different approach.
Spot screening especially made urine dipsticks and other sophisticated methods like chromatographic methods are available in most toxicology laboratories to look for these contaminants. If the sample is diluted, it needs to be documented as well as recorded, and additional screening is not necessary.