Hair Test Q & A
Hair Test Background:
Questions and Answers on Hair Tests
Q: What are the uses for hair analysis?
A: Hair analysis is rapidly becoming the test of choice for many employers during the pre-employment process. Employers have found that hair offers the ability to stop nearly twice as many drug users at the door, before they are employed. In addition, hair testing for drugs of abuse has been found to be a reliable tool in child custody cases. There is a growing interest in replacing abstinence monitoring urine programs with routine 90 day hair analysis, thereby reducing the number of times a donor must submit to a drug test and improving fidelity of detection.
Q: Why use hair analysis for pre-employment testing in the workplace?
A: Urine pre-employment testing is often called a "liquid IQ test:" Is the applicant smart enough to abstain from drug use for a week before the drug test? The most serious challenge to an effective pre-employment drug-testing program is the limited detection time of drugs in urine. Amphetamines, opiates, PCP and cocaine have average limits of detection of 3-5 days; marijuana has an average detection time of up to a week or two in urine. Conversely, drug deposits in hair remain as long as the hair is left uncut, although laboratories generally test drugs deposited in hair over a period of approximately the most recent 90 days.
Urine appears to be more susceptible to adulteration, hydration and switching. The applicant has ample time while searching for employment to plan a method to avoid a positive result in urine. High Times magazine (easily found at the newsstand) and the Internet offer methods on "how to beat a urine drug test".
Hair analysis provides a greater challenge to applicants who want to avoid drug detection. These applicants cannot replace their hair with someone else's. The applicant cannot adulterate hair by placing anything in or on the sample while in the specimen collection area. The collector takes the hair directly from the applicant and the sample is never out of sight. The applicant cannot eat or drink anything that will dilute a hair sample. We often hear of people who strip, bleach and re-dye their hair its original color. This may be effective if such an applicant is an occasional drug user, and his/her drug metabolite levels were at or near the detection cutoff levels. In most cases however, the cutoff level used by the more sophisticated laboratories is low enough that stripping the hair will not remove all of the drug that has been deposited.
Q: Is hair analysis appropriate for other workplace drug testing?
A: Because hair testing detects drug use over a long period of time, usually about ninety days, it is not an appropriate method for post-accident or reasonable suspicion testing. In both these situations, the results should detect the drug use of an individual as close as possible to the time of the incident. Urine or oral fluid testing combined with a breath or blood alcohol specimen is appropriate for this type of testing. There are employers who are using hair analysis for random testing and for abstinence monitoring following chemical dependency treatment.
Q: Is hair analysis appropriate for use by families?
A: Hair testing not only detects drug use, but also deters use. Many teenagers tell us they are able to avoid drugs by telling drug using friends "I can't use because my parents test me every three months. For kids who are stopping drug use, hair testing is useful in both identifying problems drugs, and in discouraging future use.
Q: Is hair analysis appropriate for use by probation departments?
A: The U.S. Institute of Justice has identified hair testing as an extremely useful tool in probation supervision. Hair testing at the time of intake into probation has been demonstrated to identify far more drug abusers than urine testing. Routine hair testing is actually less expensive that weekly or random urines, and is more effective is assuring abstinence and identifying drug abusers in need of closer supervision.
Q: How do drugs deposit in or on hair?
A: Current scientific research demonstrates that drugs are deposited in hair in several different ways. After ingestion, drugs can be transmitted through the blood supply; drugs can also be deposited through contact with perspiration and skin oil. In addition, drugs are externally deposited on the hair by environmental smoke or, most commonly, by smoke from the users own ingestion. As with the smoke from tobacco users, an individual's hair will be more susceptible to environmental smoke from his or her own drug use activity.
Q: What are the issues of environmental contamination?
A: Studies on environmental contamination of hair have been limited. To date, cocaine has been the principal focus of these studies and cocaine seems to be the drug most attracted to hair. Cocaine, in its smokable form, can deposit on hair. As mentioned above, the crack smoker will not only ingest cocaine, but will add more cocaine to his/her hair by mere proximity to the smoke during use. Most individuals who do not use cocaine will also not be around smoked cocaine. If an individual lives with a cocaine user, he/she could conceivably be subject to cocaine exposure in the living environment. The cocaine residue left by the user could result in both a urine and hair drug test positive if accidentally ingested in significant quantity by a non-user. If the donor lives with or spends time with a cocaine smoker, it is possible that the non-user may have some cocaine smoke deposited in his/her hair. If external exposure is limited, the cocaine should wash out of hair using normal hygienic methods. If the exposure is more intense, normal hygiene may not be sufficient to remove all of it.
Although often speculated upon, there have been no published scientific papers proving that money is a significant source of environmental contamination of hair with cocaine. Most paper money has been exposed to cocaine, but in such small amounts that handling money and brushing your hair with your hand will not produce a cocaine positive in hair.
There have been no published scientific studies of environmental contamination being a problem with other smoked drugs, such as marijuana or heroin. In addition, extensive non-controlled tests have found no marijuana positives from externally contaminated hair. Laboratory hair cleaning procedures prior to testing appear to have eliminated any potential for problems, resulting in consistently negative results for environmental exposure to marijuana and heroin.
When metabolites of these smoked drugs are detected in the hair along with the parent compound, we can be sure that the drug entered the hair after being ingested. Since hair covers a longer period of use, however, it is reasonable that a hair sample will be positive but a urine sample may be negative. Therefore, individual interpretation is required in certain circumstances. Our lab's toxicologists are available to help all clients with these issues.
Q: Will the test results really reflect 90 days use of drugs?
A: Approximately. Head hair grows approximately 1/2 inch per month, so it is reasonable to assume that if you cut the hair closely to the scalp and test the first 1-1/2 inch from the root end, you will be testing a 90 day period of hair growth.
The problem with this is that it takes hair approximately one to two weeks to grow from the hair follicle through the scalp to a level above the scalp accessible to scissors. No one recommends pulling the hair from the scalp and out of the follicle; donors would certainly object to the pain. Therefore, a hair analysis of 1-1/2 inches covers a time span of approximately 90 days one to two weeks after drug use. For this reason many employers find it useful to test both hair and urine for pre-employment purposes. Urine is useful for a current picture (last 3-5 days) of possible drug use and hair for up to a three-month drug history.
Q: How is hair analysis performed in the laboratory?
A: Hair analysis is performed by mirroring the federal forensic Substance Abuse and Mental Health Services Administration (SAMHSA) employment drug testing guidelines as closely as possible for a solid sample. Urine, of course, comes to labs in liquid form. Hair must go through additional extraction procedures in order to release the drugs from the hair before testing. From that point on, the tests are performed almost identically to urine drug testing.
1. The sample is received in the secured Toxicology Accessioning department to be verified for complete chain of custody, adequate sample volume and computer data entry. The sample is cut and weighed. Once cut into very small pieces, the sample is mixed to create as homogeneous a sample as possible. An internal chain of custody is created and a portion of the cuttings of each sample is sent to the laboratory for screening.
2. The samples are prepared and the drugs are extracted into a liquid form. As with urine, the screening process is performed by immunoassay techniques. Those samples that test negative are then reported as negative. If the screening process produces a suspected positive, a request is made from the laboratory to the accessioning department to provide a new sample from the remainder of the original cuttings.
3. The second portion of the original cuttings is then subjected to confirmation testing by either gas chromatography / mass spectrometry (GC/MS) or gas chromatography / mass spectrometry / mass spectrometry (GC/MS/MS). If the confirmation test is negative or less than the cutoff, the sample is reported as negative. If the sample is positive the laboratory reports the sample as positive.
4. Federal guidelines require a final stage for urine testing, consisting of certification review by qualified certifying scientists. Our lab's certified scientists manually review all hair analysis tests before results are issued.
Q: Which drugs are commonly tested for using hair?
A: Hair testing will identify the six drugs most often found in the work-place: amphetamine/Methamphetamine, cocaine/crack, opiates (including heroin, morphine, codeine, etc.) phencyclidine (PCP), marijuana (THC) and ecstacy (MDM).
Q: How long does it take to get hair analysis results after the sample reaches the laboratory?
A: Obviously, accuracy comes before speed. In addition, hair comes to the laboratory in solid form and requires additional sample preparation as part of the testing process. Our turnaround time from receipt of the hair sample in the laboratory is approximately 48-72 hours. Occasionally, the laboratory will require some additional time to work with a difficult sample. If a retest is requested by a client, that sample will be subjected to more sensitive analysis and will require approximately one week of laboratory time.
Q: Will the lab defend hair analysis results in court, if necessary?
A: Yes. Our lab performs over 60,000 hair tests annually and there have been very few legal challenges. Our lab has successfully defended hair analysis results in criminal cases. As with all testing performed at our lab, our professional Toxicologists are available to all clients in interpreting drug test results and provide expert witness testimony should results be questioned in administrative or legal hearings.
Q: Can hair testing go back further than 90 days?
A: Theoretically it is possible to test the entire length of hair in segments. In other words, test 1-1/2 inch segments of hair from the root end until all of the hair has been consumed. The first section would recover drugs used in the past 90 days, the second section would cover the 90 days before that, etc. However, research indicates that this type of interpretation is of questionable validity, as it is quite possible that recent use has been absorbed down the hair shaft from brushing the oils through the length of hair. Therefore, at this time and until the research supports this interpretation, our lab only tests the first 1-1/2 inch from the root end.
Q: How should a client select a hair testing laboratory?
A: There are three questions you should ask a laboratory before submitting hair analysis samples:
1. Is the laboratory certified by a forensic program?
Although there are no forensic programs that certify hair specifically, it is critical that you know that your laboratory has the forensic methods, procedures and personnel in place to properly handle workplace drug testing. The certifications you are looking for would be either SAMHSA or CAP-FUDT. These are the only two external forensic certifications available specifically for Toxicology laboratories that require routine inspections and proficiency testing designed for drug testing.
2. Does the laboratory have, and is it proficient in the use of GC/MS/MS technology?
Hair results are measured in picograms (pg.) per milligram (mg). In the case of marijuana, successful detection of the drug requires this highly advanced technology in order to obtain results at very low cut off levels. The more commonly used GC/MS is adequate for the other four drugs, but is not sensitive enough to obtain reasonable marijuana results.
3. Does the laboratory have staff and testing available seven days per week?
At a minimum, the laboratory you select should have knowledgeable staff available to answer questions.
Source: Portions of this document are adapted from Associated Pathology Laboratories, 11/13/98
