The normal range of IgE differs depending upon the age of the person being tested. The average level is 13.2 kilounits per liter for normal adults, but it is lower in infants and higher in children between the ages of 6 and 10.
Many doctors administer a screen called a total IgE test to detect the presence of allergies and allergic disorders. In each age group, IgE serum levels that are greater than one standard deviation above the mean only slightly suggest the presence of allergic disease. Levels that are greater than the mean by two standard deviations or more strongly suggest the presence of allergic disease.