Make sure you get the DDI Hair Elements Test. Not the DDI Toxic Elements test. Just giving you the heads up.
That is fine if you take it from the bottom. It will just show an older exposure though. It is best to take it as close to the root as possible so you know what is going on at that time, and not 6 months earlier. But you also don't want to take highlighted hair usually. I would take it from as close to your scalp as possible and the part that is not highlighted. You need to make sure you have no Amalgam under the crown before chelating.