for Drugs, Poisons & Toxins
Drugs of abuse actually have been measured in
nails since 1984. However, the need to test for longer
detection periods have given Fingernail testing a new
niche' to fill.
Like Hair, fingernails and toenails are
composed of a hard protein called keratin and are tested
with the same process as hair. Drugs are incorporated
into nails from the blood stream and remain locked in
the nail as it grows. Nails grow in both length and
thickness. Drugs enter the nail from the base as the
keratin is formed and via the nail bed that extends
under the full length of nail. The method of screening
for drug use in a fingernail test is the five panel,
Enzyme Multiple Immunoassay Test (EMIT). The fingernail
is put in a chemical solution to rid the nail of
external contaminants and is then liquefied.
How far does it go back?
Drugs can be identified in nail clippings
2-4 weeks following ingestion and can be detected up to
8 months after last usage. Fingernails grow
approximately 3-5 mm per month, toenails grow at a much
slower rate of 1 mm per month which means that drugs can
possibly appear in toenail clippings over 1 year after