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Hair Resources

Hair Resources

To view the Hair Testing Panels and Collection Instructions, click here.

Hair Videos

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CCDG Presentation

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Demethylated Metabolites of Oxycodone and Hydrocodone in Hair and Nail Specimens by Amy Alexander

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Direct Alcohol Biomarkers – EtG and PEth Webinar

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Direct Biomarkers of Alcohol Use by Dr. Adam Negrusz

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Hair Collection Training Video

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Hair Color Bias in Keratin Drug Testing Webinar by Joseph Jones

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Marijuana in Hair & Fingernail Webinar

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Methamphetamine and Amphetamine in Matching Nail and Hair Samples by Dr. Irene Shu

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The Future of Hair Testing

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Hair Infographics

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USDTL Hair Test In the News

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Hair Articles

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USDTL Hair Research

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Hair Poster Presentations

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USDTL Assisted Hair Research

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Foundational Hair Research

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Hair White Papers

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Hair Slide Presentations


THC in Hair

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Hair Announcements

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Hair FAQs

*Click the green and white plus sign beside each question to view the answer.

Can a hair test be manipulated by the donor?

Yes. Bleaching, perming, dyeing and straightening can affect the outcome of a hair test. Cosmetically treated hair should not be collected.

Can a second test of a different specimen type be used to prove that a previously taken test was inaccurate?

No. The results of any second collected specimen have absolutely no bearing on the validity of the results of the first collected specimen. Furthermore, each matrix has its own advantages, disadvantages and limits of interpretation.

Can a hair test determine how much or how often someone is using a drug?

No. Hair is a reservoir matrix, where drugs can collect and/or degrade over time. When testing any reservoir matrix, you are unable to back-track and determine time, dosage or frequency because there are simply too many variables involved.

Can I use the reported value (the number) from a hair, nail, meconium, umbilical cord tissue, or urine test to determine how much or how often someone is using a drug (either prescription of illicit)?

No. These specimen types act as reservoir, where drugs and their metabolites may accumulate and/or degrade over time. When testing any reservoir matrix, it is impractical to back-track to determine time, dosage, or frequency. There are too many variables involved. The reported values (the numbers) have no therapeutic or clinical value. You cannot use the number to estimate how much the donor used or to what extent the donor was exposed.

Can someone test positive in hair because of passive or environmental exposure?

Yes, drugs are incorporated into hair by three major routes: environmental exposure, sweat and sebum from the scalp and blood flow through the follicle. Environmental exposure however will only generate a positive for the parent drug. Example: methamphetamine only. The other two mechanisms lay down drug and drug metabolites. Example: amphetamine/methamphetamine positive.

Can the drug test from a maternal specimen (such as maternal hair, nail or urine) differ from the result from a neonatal specimen such as neonatal urine, meconium or umbilical cord tissue?

Yes, the results can be different. Each specimen type has its own advantages, disadvantages, threshold to positivity, and detection time window. One test does not refute the other. The test results are cumulative. For instance, if the maternal urine is positive for cocaine and newborn meconium is positive for methamphetamine, the results do not rule each other out. The appropriate interpretation is that the mother consumed both cocaine and methamphetamine.

Can the reported quantitation of drug or metabolite in hair, nail, meconium, umbilical cord, or urine be used to determine the timing of the drug use, how often the donor uses the drug, or the extent of the donor’s drug use?

No, when testing a reservoir specimen type, a specimen type where analytes tend to accumulate, you may not backtrack to determine time, dosage, or frequency. The result is positive or negative for the appropriate detection window associated with the specimen type.

Does race make a difference in hair testing results?

Hair color, not race, is one of the most important variables in determining the quantity of drug found in the hair. Dark hair binds drug tighter than light hair.

Does the sample need to be frozen?

No, the sample may be shipped ambient.

Have results been used in court cases?

Yes, the analysis of a number of tissue types for the presence of drugs of abuse has been used in every state for decades. Specifically, our umbilical cord testing has been used to provide evidence of drug use by the mother in numerous states. Additionally, the detection of drug in umbilical cord was used as evidence of maternal drug consumption in a murder case in South Carolina and that interpretation was upheld on appeal to the SC Supreme Court.

How long can drugs be detected in body hair?

Body hair has a different growth cycle compared to head hair. Body hair may go dormant and remain in place up to one year. A positive result reflects exposure up to 12 months.

How long can drugs be detected in head hair?

Once a drug is incorporated into hair, it begins to slowly leach out due to normal daily hygiene and exposure to the elements. Most drugs have disappeared by three months. Furthermore, the laboratory only analyzes the first 1.5 inches (3.9 centimeters) nearest the scalp. Hair grows at an average rate of 0.5 inches per month.

Why are both ethyl sulfate (EtS) and ethyl glucuronide (EtG) included in urine testing for alcohol use, but only EtG in fingernail or hair testing?

A: For urine testing, it is standard practice in the field of toxicology to include both EtS and EtG, because EtG is subject to bacterial production and degradation if a urine sample is contaminated (e.g. when the donor has a urinary tract infection). EtS is not subject to bacterial production or degradation, and provides a second, more reliable alcohol biomarker in these urine contamination scenarios. Other specimens types, such as fingernails and hair, do not have this issue, so only EtG is measured in those sample types.

What does a positive hair test result mean?

The only interpretation that can come from a positive hair test is that the individual used or was exposed to drug during the three months prior to collection.

Why do we test for EtG in hair and not FAEE?

FAEE is less sensitive and can produce false positives. Hairspray and other hair products can produce FAEEs in hair. There is no enzyme in our hair that can create ETG from those products.

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1.800.235.2367