Quick Answer: Can DNA Be Tested From Fingernail Clippings?
Yes, fingernail clippings can sometimes be used for DNA testing. Fingernails may contain biological material such as skin cells or other trace evidence that can contain DNA. Laboratories may attempt to extract DNA from the nail or from material found beneath the nail. The success of testing depends on the quality and amount of biological material present.
Why Fingernails May Contain DNA
Fingernails can accumulate biological material during everyday activities. This material may come from:
Skin cells from the individual
Skin cells from another person
Trace biological material transferred through contact
Environmental debris trapped under the nail
Because fingernails can collect biological material during physical contact, they may sometimes provide usable DNA for analysis.
How Fingernail DNA Testing Works
When fingernail clippings are submitted for testing, laboratories attempt to recover biological material associated with the nail.
The process typically involves:
Examining the nail sample for biological material
Collecting material from the nail surface or underside
Performing DNA extraction
Generating a DNA profile if sufficient DNA is present
If a DNA profile is generated, it may be compared to a reference sample to determine whether a particular individual may be a contributor.
Learn more about how comparison testing works here, DNA Comparison, What it can tell you.
When Fingernail DNA Testing Is Used
Fingernail clippings may be submitted for testing when a direct cheek swab from an individual is not available.
Situations where this type of testing may be considered include:
Relationship DNA testing
Investigating biological evidence after physical contact
Infidelity-related investigations
Situations where personal items must be used instead of direct samples
Because fingernail samples may contain trace biological material from contact with other individuals, they may sometimes provide useful DNA evidence.
Factors That Affect Testing Success
Not all fingernail samples contain enough biological material for successful testing. Several factors influence whether DNA can be recovered.
Amount of Biological Material
Trace DNA may be present in very small quantities, which can make analysis more difficult.
Age of the Sample
Older samples may contain degraded DNA due to environmental exposure.
Environmental Exposure
Heat, moisture, and handling may degrade biological material over time.
Contact with Other Individuals
Fingernails may contain DNA from more than one person if contact occurred with multiple individuals.
You can learn more about how laboratories interpret these results here: Multiple DNA Profiles.
Are Fingernail Samples Considered Non-Standard?
Yes. Fingernail clippings are considered non-standard DNA samples.
Non-standard samples are items that may contain biological material but were not specifically collected for DNA testing. Because of this, testing success cannot always be guaranteed.
Other examples of non-standard samples include:
Toothbrushes
Cigarette butts
Razors
Chewing gum
Clothing
Learn more about non-standard samples here: NSS Samples and DNA Testing.
Frequently Asked Questions
Can fingernail clippings contain another person’s DNA?
Yes. If physical contact occurred with another individual, skin cells or other biological material may become trapped beneath the fingernails.
Can laboratories determine how DNA got under a fingernail?
DNA testing can detect and analyze biological material, but it cannot determine exactly how that DNA was deposited.
Are fingernail DNA samples reliable?
Testing can sometimes be successful, but results depend on the quantity and quality of biological material present on the sample.
Can multiple DNA profiles be detected from fingernails?
Yes. Because fingernails may come into contact with multiple surfaces and individuals, DNA from more than one contributor may be present.
Using DNA Evidence to Find Answers
Fingernail clippings can sometimes provide a source of biological material when direct samples are not available. Because fingernails can accumulate skin cells and other trace evidence through contact, laboratories may attempt to recover DNA from these samples.
Understanding how fingernail DNA testing works helps individuals determine whether this type of sample may be suitable for their situation.
