DNA testing hair procedures differ from the usual buccal swab techniques which are commonly used in paternity and other tests involving home kits. They do, however, produce a result which is every bit as reliable as those of the standard tests. Of course, it is essential to make sure that you have the hair of the correct person, as it is so easy for hair of one person to become mixed with another if they spend time in close proximity. When swab tests cannot be used, you need to find an alternative, and if you do have hair available it can be one of the best ways to circumvent the problem.
Hair tests are also commonly used in criminal investigations, because hair can often be inadvertently left at the scene of a crime. Again, the biggest problem is being able to definitely identify the hair as belonging to the suspect, once you have proven that the DNA matches that found at the crime scene. Hair is also relatively resilient, and can often be used to identify a corpse which is otherwise hard to identify, provided that the hair DNA exists on a database somewhere.
It is rarely necessary to use hair in a standard paternity case, because it will usually be a simple matter to take a swab in the normal way. These swabs are easy to use, completely pain free, and they can be sent through the mail to a DNA testing center. The only case where it is not possible to use a swab is where one of the parties who needs to be tested is not volunteering, or when they are not there. If you have a hair sample, that can be forwarded to the testing center and the results will be exactly as if a swab had been taken.
There are other family cases which may be far more complicated, such as when a blood line needs to be traced back over several generations. Often, hair will have survived when other parts of the body have already decomposed, making it an ideal subject for this type of testing. The purpose will be to ascertain whether or not a certain person has DNA which has strands that match those of the existing known family.
When you are using DNA testing hair will necessarily deteriorate as a result of the testing procedure, so it is important to get a definitive result the first time. If you have a larger sample of hair, you will get a second chance, but in many cases you will not. If you can guarantee that the hair you are testing is from the right person, then this type of test will be among the most accurate you could carry out. If you may need to rely on evidence in court, it is best to document and record your DNA testing hair technique.