Single allergen sensitization tests may miss cases in children
medwireNews: There is significant discordance between the results of allergen-specific skin prick tests (SPT) and allergen-specific serum immunoglobulin E (sIgE) levels for identifying aeroallergen sensitization in children under the age of 4 years, a study finds.
The researchers say their findings indicate that both tests should be performed when diagnosing allergic sensitization in young children at high risk for asthma, in order to avoid missing cases.
The team, led by Gabriele de Vos (Albert Einstein College of Medicine, New York, USA), analyzed SPT and allergen-specific sIgE test results for seven common aeroallergens in 40 children (18 to 48 months of age) who were receiving care for wheezing with significant asthma symptoms at an inner-city hospital-based pediatric asthma center.
All patients were atopic, according to positive SPT or sIgE test results to an environmental allergen, and were at major risk for developing asthma, as indicated by a history of eczema or having one parent with a history of asthma.
As reported in the Annals of Allergy, Asthma & Immunology, 80% of children with one or more allergen sensitizations would have been missed if only SPT had been administered, while in 38% of children one or more sensitizations would have been overlooked with sIgE alone.
According to the k statistic, strength of agreement in detecting allergic sensitization by the two methods was poor (k < 0.20) or fair (k = 0.21-0.40) for nearly all allergens tested; only mouse epithelia testing resulted in moderate agreement (k = 0.50).
Children with high sIgE levels (≥300 kU/L) were especially likely to have a negative corresponding SPT result, while children with levels below 300 kU/L were as likely to have positive skin results with negative corresponding serum IgE results as vice versa.
The authors estimate that an average of 42% of all sensitizations that were diagnosed by combined sIgE tests and SPTs would have been missed if only SPT had been administered. If sIgE testing alone had been performed, a mean of 13% of all sensitizations would have been missed.
"It may be necessary to perform specific sIgE testing in addition to an SPT when accurate diagnosis of aeroallergen sensitization is required to define an appropriate intervention," they conclude.
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By Peter Sergo, medwireNews Reporter