What is the best food allergy, sensitivity or intolerance test?

Avoidance &challenge: Every test out there is imperfect. This is because there are many different mechanisms of food sensitivities- some mediated by igg, e, a & m antibodies, some by lymphocytes, some by inability to digest (lactose), some by inability to metabolize (nightshades) and there aren't tests for all of these. Avoiding suspect foods for 5 days to 1 month & challenging to see if you react is still the best test!