Continuous reference intervals for total serum immunoglobulin E in neonates and children.

Immunoglobulin E (IgE) is a group of antibodies involved with allergic sensitisation. Levels of total IgE change with age and tend to be higher in individuals with allergic diseases than in those without. To improve the clinical utility of total IgE, this study aimed to establish continuous paediatric reference intervals (RIs) for healthy individuals. The study participants consisted of healthy term neonates and children aged 30 days to 18 years. Venous blood samples were collected, and total serum IgE concentrations were measured by performing a fluoroenzyme immunoassay. Fractional polynomial regression modelling and quantile regression were applied in the statistical analysis to generate continuous RIs. A total of 441 samples were analysed for total serum IgE, including 12 neonate samples and 429 paediatric samples from birth to 18 years of age, with males representing 51.5% (n=227) of the samples. For individuals without allergic conditions (n=305), the RI formulae for 2.5th percentile and 97.5th percentile were 2.00 and 37.29+101.95∗(age/10), respectively. For individuals with allergic conditions (n=136), the RI formulae for 2.5th percentile and 97.5th percentile were 1.50+0.30∗(age/10) and 1751.73+14.82∗(age/10), respectively. This study established continuous paediatric RIs for total serum IgE in otherwise healthy term neonates and children with and without allergic conditions. The continuous RIs generated from this study showed the age-based dynamic changes and allergy-specific differences for total serum IgE.