IgE testing in capillary blood.

Serologic IgE testing is generally performed using serum, obtained by venepuncture. We tested whether paper-absorbed and eluted capillary blood, obtained by a less invasive method (finger prick) could be used for allergy testing in young children. This was performed by comparative IgE testing, using paper-absorbed blood/serum and serum. Practical applicability of the procedure was tested by assaying paper-absorbed and eluted blood, obtained from 640 children with complaints of prolonged coughing, for IgE to airborne allergens. We found that IgE testing, using paper-absorbed/eluted material and serum yields virtually identical results (mean ratio for positive samples: 1.01, 95% confidence interval: 0.58-1.75). Blood spot testing revealed that sensitization to inhalant allergens is not uncommon in preschool children (13% positive radioallergosorbent test [RAST] tests), which means that this procedure is a useful method for assaying allergic sensitization in children.