gcsjr

I believe that the "Set Point" is the strength of the allergen that actually generated an allergic response (but I don't know whether 6 is just a relative number or it's a specific level that would tell the doctor whether you're very allergic or not very allergic).

The references to an 11mm and 9mm wheal are references to the size (in millimeters) of the red bump (wheal) after your body reacted to the allergen. The size of each bump is compared to the saline (water) control and the histamine control (which everyone should react to) to determine what things you're allergic to. So, if the bump at the saline injection site is 2mm and you get an 11mm bump at the spot where they test ragweed, you're probably allergic to ragweed.

The size of the bump give some sense of how allergic you are but I don't think it's necessarily proportional.