If someone has been clean from all drugs for 9 months but then smokes crack for one night can they pass a hair follicle test after two months?
Hair tests can test positive for as long as the hair is still
there, however, crack, being a very low dose drug that clears the
system very fast may not even be detectable if it was only one
night, but rather than run that risk, get a specialty shampoo,
available at most headshops, or shave your head.