What does the term 'chain of custody' mean, in relation to DNA testing.

This is a critical phrase that is relevant if you ever want to use the outcome of a DNA test in a court. It simply means that there is a clear chain of custody (of the samples) from when they were taken, to the final result being produced and sent out.

To demonstrate a 'chain of custody' a third in dependant party is normally involved. For example this may be your Doctor who will take the samples from you and the child, and confirm the identity of the individuals with passports and photographs, for example.

The samples will then be sealed and sent off by the Doctor to the testing company. By doing this there is a clear chain of custody (which must be maintained by good laboratory practice, by the DNA testing company), and any outcome can be presented in a court.

The type of DNA test used to present evidence in court must provide a degree of certainty at the 99.99% level. Anything below this will not be accepted in an American Court. This should be considered before commissioning and DNA testing work.