• Fingernail Testing

    Fingernail Testing

    Fingernail testing is emerging as a popular means for drug and alcohol testing.

    Like hair strand testing, fingernails are a keratinized protein. Fingernails are porous and compounds become entrapped and bind within the structure.

    Compounds are incorporated into fingernail by four main routes.

    • The first route of incorporation, just like hair, is environmental exposure. If someone is handling drugs, the drug gets on the nail and works its way into the pores and binds to the keratinized protein.

    • The second route of incorporation is the sweat and oil of the skin surrounding the nail deposit drug and drug metabolite into the nail.

    • The third route of incorporation is the blood flow in the germinal matrix deposits drug and drug metabolite into the nail when it is formed.

    • Lastly, drug and drug metabolite are deposited to the underside of the nail plate by the blood flow in the nail bed. These four very different routes of incorporation are superimposed on top of each other rendering a very complex drug history picture.


    The entire process for fingernail drug and alcohol absorption can take up to 6 months – depending on the health of the individual.

    Therefore, we know that with fingernail testing Рthere is a potential for a detection window of up to six months. Just like hair and urine, a negative result is not proof of abstinence, just the lack of evidence. A positive fingernail result for most drugs may be explained by drug use at any point during the 6 months prior to the collection.

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