There are many situations in which someone may be legally required to undergo drug testing, including agreements between divorcing spouses, child custody arrangements, probation, DUI or DWI arrests.
These two sample types, hair and nail, are collected under direct observation, which makes it difficult to adulterate or cheat. Body hair and toe nails accumulate more biomarkers due to their slower growth rate, which in turn extends the detection window. Both hair and nail follicle testing share the disadvantage of not being able to detect recent or short term drug abuse within the most recent 2 weeks. It takes 7 to 10 days for any drug(s) to metabolize through the blood vessels and grow out either through the hair follicle or the nail bed.
Over the last few years, hair testing has become popular with employers throughout the United States. Hair testing provides nearly twice the number of positives due to its longer detection window, and it’s hard to adulterate the specimen. But if your desired testing window is within the past 12 hours, it would not be recommended that a hair, nail, or even urine test be conducted.