This "voodoo allergy" testing is called surrogate testing.  It is very
accurate if the intermediate person is not allergic or sensitive to the
offending food.  So, the surrogate should be tested independent of your son
to verify.  Personally, my chiropractor used muscle testing through
surrogate testing & diagnosed my son with a sensitivity to dairy 5 years ago
(age 4.5).  After taking him off of the dairy back then, his constant ear
infections & non-stop fluid filled ears totally cleared up.  To this day, if
he gets into dairy, he will get the dark under-eye circles, and if too much
is ingested, progress to a sinus or ear infection.  We've had a few
substitute teacher learning experiences.  I had weaned him at 6 mos. to a
dairy based formula and at 7 mos. he had his first ear infection and the
viscious cycle of ear infections & fluid filled ears & ear tubes went on &
on until removing dairy.  I never knew of a dairy allergy or sensitivity at
that time b/c I thought food allergies caused hives, wheezing, etc.  We've
come a long way.

Janice