Serum immunoglobulin concentrations in preschool children measured by laser nephelometry: reference ranges for IgG, IgA, IgM.

Serum immunoglobulin concentrations were determined on sera from 298 healthy children aged six months to six years using the Hyland laser nephelometer PDQ system. Age-specific 95% reference ranges for serum IgG, IgA and IgM are presented; considerable care has been taken to ensure statistical validity of the reference ranges. The wide range of values in children under two years suggest that measuring immunoglobulin concentrations in this age group is of little value in diagnosing immunodeficiency.