Think of it as high speed muscle testing. All that can tell you is that you are reacting to something negatively or positively.
If negative it could be an issue, but depending on the operator, the lowest (non reactive) items are also treated because having no reactivity can mean your body has given up on these issues.
Other things that may effect reaction time; SV40, Oncoviruses, Heavy Metals and some immune suppressing critters and viruses..
..as for the Wool thing and emotions, this is a homeopathic energy that was tested, not actual wool. That is why it is not possible to distinguish between the homeo's emotional remedy or wool allergy.