The document discusses several studies related to allergies and atopy. It summarizes that: 1) A study of over 8,000 people in the US found that total IgE levels were only associated with asthma in those who tested positive for at least one specific allergen. 2) Another study identified that testing for 10 common allergens allowed detection of over 95% of atopic subjects, but testing for 15 allergens was needed to identify all atopic individuals. 3) Parental allergen sensitization increases the likelihood that their 18-year-old offspring will be sensitized to the same allergens. Testing parents and children for six common allergens showed this relationship.