A comparison of different allergometric tests, skin prick test, Pharmacia UniCAP and ADVIA Centaur, for diagnosis of allergic diseases in children.

Abstract

The diagnosis of allergic disease is performed by skin prick tests (SPT) or through the demonstration of specific IgE in a blood sample via an in vitro test. The measurement of IgE concentration against allergens provides critical information in clinical allergy. Standardized and reproducible methods contribute to the quality of diagnosis and treatment of allergic disease. In this study we evaluated the performance of a new specific IgE method, developed by ALK-Abellò for Bayer Diagnostics to run on their ADVIA Centaur immunoassay system. One hundred and fifty-one children with allergic diseases (both food and inhalant allergies) were tested for specific IgE (sIgE) via SPT and in vitro tests (UniCAP system, Pharmacia, and ADVIA Centaur immunoassay system, Bayer Diagnostics) and the test results were correlated with the clinical data. Statistical analysis revealed no significant difference between the two in vitro tests compared with clinical history. The sensitivities and specificities are similar, but the UniCAP system method has higher sensitivity. In the children with cow's milk allergy, the UniCAP system has sensitivity of 91% and specificity of 70%; the ADVIA Centaur immunoassay has sensitivity of 82% and specificity of 74%. In hen's egg allergy, UniCAP system has 94% sensitivity and 64% specificity, and the ADVIA Centaur system has 88% sensitivity and 52% specificity. In inhalant allergies, the two methods show statistically similar performances for both grass pollen allergies (UniCAP sensitivity 100%, specificity 73%; ADVIA Centaur sensitivity 95%, specificity 79%) and in the dust mites allergies (UniCAP sensitivity 91%, specificity 62%; ADVIA Centaur sensitivity 86%, specificity 64%). In cat allergies, the systems showed equivalent results (UniCAP sensitivity 100%, specificity 71%; ADVIA Centaur sensitivity 100%, specificity 70%). Using the UniCAP system, the geometric mean of sIgE values in children with clinical allergy is significantly higher than in sensitized ones. The ADVIA Centaur system shows a similar trend with the exclusion of cow's milk and Dermatophagoides farinae allergens. With this last method the mean value of sIgE is higher in sensitized than in symptomatic children. The new ADVIA Centaur method compares favorably with the results obtained on the UniCAP system. If other studies continue to confirm this data, then the advantages are numerous: the use of only a small quantity of serum (25 micro l per allergen), rapid turnaround time, minimal hands-on time, and no interference from IgG.