New childhood and adult reference intervals for total IgE

Patient demographics are shown in Table I. Total IgE concentrations were measured by using the ImmunoCAP 1000 instrument (Phadia, Uppsala, Sweden) using IgE calibrators traceable to the 2nd International Reference Preparation 75/502 of Human Serum Immunoglobulin E from the World Health Organization. Reference intervals cited in the ImmunoCAP System's package insert were based on 466 healthy children from 2 independent studies, both using the PRIST immunoassay system.3,5 Reference intervals calculated from these combined studies gave an upper limit of 84 IU/mL (geometric mean ± 2 SD) for their 5-year-old group and an upper limit of 148 IU/mL for children aged 10 years.