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Fequently Asked Questions
1. What is hair screening? A test for substance abuse that utlizes a small sample of hair to identify specific drugs used by the person being tested. It is the most accurate method of detecting substance abuse. The lab's state-of-the-art hair screening method uses enzyme-immunoassay (EIA). EIA measures the drug molecules permanently entrapped in the hair which were incorporated following introduction into the body and subsequent adsorption into the bloodstream. 2. How effective is hair screening in detecting drug users? In side-by-side comparison studies with urinalysis, the cocaine, PCP, opiates, and methamphetamine assays have proven hair analysis far more effective than urine in identifying low-level drug use. The marijuana screen is currently less sensitive than the other drugs in identifying low level drug users, but is considered roughly equal to urinalysis in identifying marijuana users. 3. What drugs can be detected in a standard hair screen? Cocaine (cocaine & benzoylecgonine), marijuana, opiates (Codeine, Morphine & 6-monacteyl morphine), methamphetamine (Meth/amphetamine & Ecstasy), and phencyclidine (PCP). These five drug classes are mandated for testing by the Federal Government. 4. How do drugs get into hair? As drugs circulate in the blood stream, they enter and nourish hair follicle cells. As the cells grow, they trap the drug molecules within the hair cells and are eventually "sealed" in the keratinized hair shaft. Thus, the amount and time the drug(s) are in the blood stream can be evaluated from a hair sample. 5. What time period does a standard test cover? A standard screen covers a period of approximately 90 days. The hair sample is cut as close to the scalp as possible and the most recent 1.5 inches are tested. 6. How does hair screening compare to urinalysis? One major advantage is the wider window of detection available with hair. Cocaine, methamphetamine, opiates and PCP are rapidly excreted and usually undetectable with urinalysis beyond 72 hours after drug use. The detection period for hair is limited only by the length of the hair sample and is approximately 90 days for a standard screen. Additional advantages if hair screening are (1) non-intrusive collection procedures (2) virtual elimination of test evasion (3) greater accuracy through test repetition capability. The combination of an increased window of detection and resistance to evasion makes hair far more effective than urinalysis in correctly identifying drug users. Start of FAQ
More Frequently Asked Questions
1. How soon after use can a drug be detected in hair? 1. How soon after use can a drug be detected in hair? It takes approximately 4-7 days from the time of drug use for the affected hair to grow above the scalp. Body hair growth rates are generally slower. Body hair can be used to determine drug use, but cannot be utilized to define a time frame of drug use. Back to more FAQ 2. What is the shortest time period that can be accurately evaluated? The minimum time period is approximately one month (1/2 inch). Due to variability of hair growth rates, as well as screening sensitivity limitations, EIA cannot go back in time to determine if an individual used drugs on a particular day or week. Back to more FAQ 3. How fast does head hair grow? Studies indicate that hair collected at the crown of the head grows on the average approximately 1.3 cm (or 1/2 inch) per month. This growth rate varies among people (estimated at + .2 cm per month, consequently there is some (+ 1 week) time variation possible. Back to more FAQ 4. How much hair is needed? A standard screen with GC/MS confirmation requires 40+ milligrams of hair or approximately 50 - 70 strands. The thickness of different types of head hair (thick brown vs. thinning gray) is the basis of this variation. Back to more FAQ 5. Can tests be run on people with little or no hair? Hair can be collected from several head locations and combined to obtain the required amount of hair. In addition, body hair may be used as a substitute to head hair. In the rare case where no hair is collectable, complete urine/adulteration testing may be utilized. Back to more FAQ 6. Does body hair give the same type of results as head hair? Yes, body hair can be used to test for the five standard drug classes. Body hair growth rates vary and are slower than head hair. Most body hair is genetically controlled and replaced within one year. Therefore, it is difficult to accurately represent the time period of a standard screen with body hair. Back to more FAQ 7. Can hair collected from a brush be used? No. The lab requires a hair sample to be collected using proper chain-of-custody protocols that will withstand a legal challenge. Back to more FAQ 8. How are cut-off levels established? The lab's cut-off levels are generally accepted industry-wide and are based in part by minimum detection levels for GC/MS confirmation. Back to more FAQ 9. What are the differences between hair cut-off levels and urinalysis cut-off levels? In general, cut-off levels for urinalysis have been established to reduce the possibility of an evidential false positive result due to passive inhalation. A true comparison of hair/urine cut-off levels is impossible, since the time frame differs (90 days vs. 5 days). SAMHSA's (NIDA's) recommended cut-off levels for forensic urinalysis tests are expressed in nanograms per milliliter (ng/ml) of urine. Hair cut-off levels are expressed in nanograms per milligram (ng/mg) of hair. Back to more FAQ 10. Does the lab perform GC/MS confirmation of all positive hair results? Yes, automatic confirmation utilizing GC/MS for ALL specimens that screen positive (opiates, PCP, methamphetamine, cocaine and marijuana). Back to more FAQ 11. Can hair be affected by cross-reacting substances such as over-the-counter medications? Enzyme-immunoassay antibodies (EIA), similar to those used to test urine, are used for the initial screening test for drugs of abuse in hair; therefore the potential for substances such as over-the-counter medications to cause a false positive screening result does exist. To eliminate the possibility of reporting a false-positive due to cross-reactivity, the lab automatically confirms by GC/MS all positive results for methamphetamine, opiates, PCP, cocaine and marijuana. Back to more FAQ 12. Does external exposure to certain drugs, like marijuana or crack smoke, affect the hair results? All hair samples that produce a positive screening result are washed extensively to remove external contamination and may be re-screened for the potential positive drug. If the secondary hair screen is positive and the ratio of the wash solution is greater than 10% of the confirmation result, the lab will consider this sample contaminated. If the ratio of the wash solution is less than 10% of the confirmation result, the lab will consider the sample as positive. Marijuana does not follow the wash patterns of the other drugs. To rule out the possibility of external contamination for marijuana, the lab detects ONLY the metabolite (THC-COOH) which is only produced by the body and cannot be an environmental contaminant. In addition, the lab will NOT analyze pubic hair for the presence of the THC-COOH metabolite. Back to more FAQ 13. Does treatment of the hair affect test results? Extensive bleaching, perming and dyeing may damage the protein matrix of hair allowing a portion of the drug within the hair to be extracted, thus lowering the final quantitative result with certain drugs. Normal hair washing helps to remove external contamination. Commonly used hair products (e.g. shampoos, conditioners, sprays, mousses or gels) have no significant effect on hair results. Back to more FAQ 14. What is done with the excess hair that is not tested? The hair not used from the time period being tested (i.e. three months equals 3.9 cm) is stored in the chain-of-custody sample acquisition pouch. Negative hair is stored for one month. Positive hair is stored for one year. Back to more FAQ 15. How long are positive and negative test result reports kept on file? All laboratory records and test results are kept for a three year period or as mandated by Law. Back to more FAQ 16. What other drugs are available to be tested in hair analysis? Currently, hydrocodone, hydromorphone and oxycodone. Detection of these compounds is possible by special arrangement with the Laboratory. Back to more FAQ 17. What is external contamination? Drugs that are deposited on the hair shafts by any means (dust, sweat, combs, etc) are considered external contaminants. These contaminants are removed prior to testing being performed. Back to more FAQ
DEFINITIONS Chain-of-Custody - Protocol established to maintain integrity and confidentiality of all samples submitted. Chain-of-Custody begins with the collection procedure but must be maintained throughout shipping, testing, result reporting and record/specimen storage. Gas Chromatography/Mass Spectrometry (GC/MS) - Highly specialized method of analysis used to detect presence of substances in a specimen. GC/MS is considered the "Gold Standard" and represents "state of the art" technology. Parent Compounds & Metabolites - All drugs are taken into the body, utilized and then broken down into compounds known as "metabolites." The original substances are referred to as "parent compounds." Washing - Process of cleansing unrelated matter and chemicals from the hair sample prior to testing. This procedure eliminates traces of external contamination from the hair sample. Portions of each wash are saved in case a sample tests positive at which time the ratio of the drug found in the wash will be compared to the ratio of the drug found in the hair.
Window of Detection - The period of time that a particular test
correlates to. This time frame is dependent on the length of the hair
sample tested. On the average, hair grows at a rate of 1.3 cm (about .5
in) a month. The EIA Standard Screen requires 3.9 cm (about 1.5 in) and
will detect drug usage over an approximate 90 day period.
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