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Fingernail Resources

Fingernail Resources

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

Fingernail 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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Fingernail Collection Training Video

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Follow a Fingernail Specimen Through the Lab by Joseph Jones

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Following a Fingernail Specimen Through the Laboratory

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Long-term Biomarkers for monitoring DUI/OWI offenders

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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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USDTL Fingernail Testing FAQ

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Wisconsin Counties Use Long-Term Alcohol Biomarker Testing

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Fingernail Infographics

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USDTL Fingernail Test In the News

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Fingernail Articles

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USDTL Fingernail Research

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Fingernail Poster Presentations

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Fingernail Slide Presentations


THC in Hair


Fingernail Drug Testing For Alcohol And Substances of Abuse

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Fingernail Announcements

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Fingernail FAQs

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

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 nail test be used to prove that a previously taken hair test was inaccurate?

No, the result of any second collected specimen has absolutely no bearing on the validity of the result of any first collected specimen because you have no idea what the donor did between time A and time B.

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 fingernail because of passive or environmental exposure?

Yes, environmental exposure versus ingestion must be resolved when interpreting drug tests using fingernails.

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 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 do drugs get into nails?

Drugs are distributed via the blood supply to the nail cells and the nail bed. Nails grow not only in length but in thickness as well. As the nail grows in thickness, it creates layers of drug history.

How much fingernail needs to be collected?

The optimum amount of nail clippings needed is 100 milligrams. If trimming all 10 fingernails, each clipping must be at least 2 millimeters to 3 millimeters long.

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.

Will one-time drug use be detected in Fingernail Testing? How many times would they have to use drugs for it to be detected in nails?

Single doses do not guarantee a positive result. The number of doses required to generate a positive result is highly variable between donors.

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Contact USDTL

1.800.235.2367