Fingernails, like hair, are made of the protein keratin and tested with the same process.  The method of screening for drug use in a fingernail test is a five panel, Enzyme Multiple Immunoassay Test (EMIT).  The fingernail is put into a chemical solution to rid the nail of external contaminants and is then liquified.

Five drugs are tested which are Cocaine, Amphetamines, Opiates, PCP and THC.

Fingernail samples can represent drug use up to approximately 4-8 months.  Fingernails can be clipped and if the length does not allow, fingernails can be shaved for sample collection.