Forensic Drug Testing Lab
Fingernail Drug Testing
Highly stable, simple to collect, and easy to ship and store, fingernails provide a test sample that is at the cutting edge of drug and alcohol testing. Fingernails are made up of keratin, the same material that hair is made of. As the nail grows, substances can pass from the blood vessels below the nail into the keratin fibers where they become trapped. Fingernails are four times thicker than the typical strand of hair and often capture more of a substance than hair can. Biomarkers become locked in keratin fibers along the entire length of the nail, and can be detected up to 3-6 months after drug or alcohol abuse. Environmental exposure to illicit substances can be detected immediately in nail samples. When drugs or alcohol are ingested, biomarkers can be found in nails as early as 1-2 weeks after. The time period during which drug or alcohol ingestion can be detected depends on the substance used, the amount used, and personal metabolism. Fingernail samples are clipped and collected by the donor in front of a trained collection staff member. A clipping of 2-3 mm long (about the width of a quarter) from all ten fingernails will give about 100 mg of sample, the ideal amount for screening and confirmation. Larger profiles may require more. We recommend weighing the specimen on a jeweler's scale.
Click here to view our fingernail collection instruction slides.
Click here to download the fingernail and hair drug panels.
Click here to view the Fingernail Resources page.
- 17 Panel
- 16 Panel
- 15 Panel
- 14 Panel
- 12 Panel
- 10 Panel
*Click the green and white plus sign beside each drug class to view the substances within each class.
A. Once verified, mark the Picture ID Verified box on the Custody and Control Form.
B. Record the donor’s ID number. This may be the Social Security number, Driver’s License number, Medical Record number, Employee number or any other number of your facilities choosing.
C. Record the donor’s name (optional).
D. Mark the specimen matrix and location.
E. Mark the appropriate reason for testing.
F. Mark the panel ordered for this collection.
G. Record the Collection Site Facility information if it is different than the Account Information at the top of the form.
By Phone: 1.800.235.2367
Business Hours (CST)
Monday 6am - 8pm
Tuesday 6am - 8pm
Wednesday 6am - 8pm
Thursday 6am - 8pm
Friday 6am - 8pm
Panel Name: Nail Testing
Panel Description: Nail Testing Drug Panel
Collection Container: Foil in Secure Envelope
Sample Amount: 100 mg = 10 clippings @ 2mm thick (Larger profiles may require more. We recommend weighing the specimen on a jeweler's scale.)
Storage Conditions: Room Temperature
Transport Conditions: Ambient
Method: Initial screening test with confirmation of presumptive positives
Turn-Around Time: 1 day for negatives / 2-3 days for positives
- White Papers
Can a nail test be used to prove that a previously taken hair test was inaccurate?
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.
How do drugs get into nails?
How much fingernail needs to be collected?
If the quantity of drug or alcohol metabolite detected is high, could that be an indication that the donor (1) was consuming a large amount, (2) was using recently, or (3) was using frequently?
There are too many variables for anyone to know time of use, dosage, or frequency from the result(s) of a drug test. Reservoir matrices such as hair, fingernail, umbilical cord, and meconium continuously collect drug and alcohol biomarkers. This makes it difficult to determine specific details of use. Because the biomarker is collected over a period of time, the results represent total accumulation that cannot be pin-pointed to specific times/dates/dosages, etc.
Q: 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.
Why was one matrix positive and another negative on the same donor?
There are several explanations for this.
- Different sample matrices have different detection time frames. The result of any second collected specimen has no bearing on the validity of a first collected specimen. For example, a hair sample with a three month window of detection might test positive for a particular substance, while a urine sample from the same donor, with a 2-3 day window of detection, might test negative. In this case, the donor has used that substance within the past three months, but may not have used it within the most recent three days.
- The result of any second collected specimen has no bearing on the validity of a first collected specimen. Therefore, a negative result observed for the umbilical cord does not refute a positive result observed on the maternal urine specimen and the reverse is true as well. There are many legitimate reasons for discrepant urine and umbilical cord results.
- The urine specimen was a screen only result and was not confirmed using an appropriate mass spectrometric method. The screen only urine result is a clinically valid result, however, without an appropriate mass spectrometric confirmation, the urine result has no value in a forensic proceeding.
- Lastly, some placentas can prevent some compounds from reaching the fetus. There are documented cases of maternal ingestion without in utero exposure.
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?