How do you reconcile differences between SPT and serum IgE testing for aeroallergens when preparing AIT?

The 2008 Allergy Diagnostic Testing Practice Parameters would note as follows:

"The precise sensitivity of these immunoassays (serum IgE testing) compared with prick/puncture skin tests has been reported to range from less than 50% to greater than 90%, with the average being approximately 70% to 75% for most studies."

Thus, there is a well-known discordance between SPT and serum IgE testing. When preparing AIT, I personally err towards adding sensitizations since it's a significant investment of time for the patient. However, my opinion is that the AIT preparation comes at the discretion of the allergist preparing the AIT. This discretion would be based on the clinical history, testing results, and the patient's goals/preferences taken into context.

I base my decision on which allergens to include based on the clinical history of symptoms and cross-reactivity relationships to reconcile any differences. Skin testing has a higher sensitivity, but I’ve had patients test negative on skin tests only to test positive on serum IgE testing. If symptoms correlate with the allergens and the patient wishes to pursue allergen immunotherapy (AIT), I have used the serum results to prescribe their AIT mix.