The elevated total IgE, in spite of some well-known limitations, is frequently included as a diagnostic criterion for allergic diseases. There are many kinds of in vitro allergy diagnostic product to measure the concentration of total IgE. Because the multiple allergy screening kits, such as AlleryScreen® (Mediwiss Analytic GmbH and r-biopharm), Euroline (Euroimmun AG), Optigen® (Hitachi Chemical diagnostics, Inc) and Polycheck® (Biocheck GmbH), are low-cost test, their uses in clinic are rapidly growing nowadays. However, there are few comparison studies for total IgE level between multiple allergy screening kits and ImmunoCAP, a well-known quantitative diagnostic kit for allergy. The aim of this study is to compare the total IgE concentration in serum by Protia Allergy-Q, a multiple allergy screening kit, with ImmunoCAP and to evaluate the clinical usability of Protia Allergy-Q.
Methods
392 patients who visited the Hospital of Korean Medicine, Kyung Hee Medical Center were enrolled in this study. Informed consent was obtained from all patients. After five milliliters of the whole blood was collected in a vacuum tube, serum was separated by centrifugation at 3,000 rpm for 5 min, aliquoted into several round-bottom tubes and frozen at -80°C until use. ImmunoCAP was tested by Green Cross Laboratories (Yongin-si, Korea) and Protia Allergy-Q was performed by us. The correlation between two assays was analyzed by Passing-Bablok regression analysis.
Results
The average of total IgE from 392 sera measured by ImmunoCAP and Protia Allergy-Q was 167.1 and 149.4 kU/l, respectively. Passing-Bablok regression analysis demonstrated that ImmunoCAP and Protia Allergy-Q exhibited almost perfect correlation (intercept, 5.6676 [95% confidence interval {CI} 4.3282, 6.9388] and slope, 0.8676 [95% CI 0.8211, 0.9107]).
Conclusions
Protia Allergy-Q, a multiple allergy screening kit, is a low-cost screening test for patients with suspected allergy. It provides 60 kinds of specific IgE level but also total IgE level. Even though it is a semi-quantitative assay, total IgE concentration tested by Allergy-Q is nearly equal to that by ImmunoCAP. Therefore, it may be very convenient tool to measure not only specific IgE but total IgE concentration.