Paternity Hair Testing
Paternity tests which use hair as as a DNA sample work in much the same way as ones which use blood samples or buccal swabs do. The sample is obtained, sealed and sent to a laboratory where it is tested both inclusively and exclusively to either determine the paternity of a man or to determine that he is not the father of a child, respectively.
It is not actually the hair itself that laboratory DNA testers use in paternity hair testing, but actually the hair follicle that the hair grows out of. Often when a few (say, three or four) hairs are removed from the head, or indeed any other part of the body, usually one of those will have pulled the follicle with it. This part of the hair contains genetic information and the DNA strands which are compared in both individuals. In some court cases men shave their heads in order to prevent a hair sample being obtained, yet hair from any part of the body can be used; even downy hair from the arms and legs.
Paternity test samples are very different to hair samples needed for legal drug testing. Hair is good for testing for drugs as it grows slowly and in each part contains the drug taken; therefore it acts like a time line and there is no need for the follicle to be included. If you are carrying out a home paternity hair test then you should always pluck the hair before you send it, or you could invalidate an expensive testing kit.
Hair testing is one of the simplest DNA tests that can be carried out and because of this, individuals should only need to wait around one, possibly two weeks for results. It's always a good idea to contact the laboratory to give them your phone number, so that if they obtain results early they can let you know via phone call.