Tag: How much hair is needed for a drug test

Hair testing

Ask the Experts: Hair drug test collections

May 18, 2021 By

The amount of hair needed for a hair drug test is approximately 100 milligrams made up of the first 1-½ inches from the root end. The hair is typically cut from the crown of the back of the head in a manner where it will not be as noticeable. Learn more about hair drug test collections.