There are many kinds of in vitro allergy testing kits to be developed by various manufacturers and widely utilized for diagnosis of allergy. The in vitro testing kit for allergy measures the concentration of IgE in patient’s serum or plasma, which binds to allergens coated at the membrane support. Nitrocellulose membrane is usually used to immobilize many kinds of allergen. Since the line blot assay rather than dot blot assay has good repeatability, reproducibility and robustness, many types of in vitro allergy testing kit adopt the technology, so that many kinds of allergens are generally arrayed by 20 ~ 30 lines per test strip. However, the traditional line blot assay is difficult to increase the number of testing items because of its long-narrow structure, which is easy to spill-over of solution during the incubation of sample or reagents.
Methods
If the number of tested allergens should be increased, it can be achieved by 3 different options. One approach is to elongate the length of the strip without changing of gap between the lines. In this case, it must devise the solution to overcome the problem of spill-over. Another option is to coat the allergen more compactly in the equal-sized testing strip. But, if the bands in the testing strip go to be thinner, the robustness of assay would be diminished. The other possibility is to arrange the strips of two or more. It is a common way to be adopted by all the allergy testing products, where use two testing strips per single patient. However, we developed a novel technology, Parallel Lines Array (PLA), can test simultaneously up to 64 lines in a single strip.
Results
We produced 2 kinds of narrow strips of width of 1.95mm and then assembled the strips side by side in single allergy testing kit. The each strip has 25 or 32 lines to be coated with allergen or our standard, so we can measure 50 or 64 items in a single test. Since the Protia Allergy-Q use only one strip per single patient, rather than two strips per person at traditional allergy testing kits, it can save the testing time and blood volume. Furthermore, its diagnostic performance was compare to ImmunoCAP with 1,799 paired assay, which resulted in good concordance for most allergens (k=0.713-0.898, p<0.001).
Conclusions
The Protia Allergy-Q, adopting PLA technology, has comparable diagnostic performance to traditional multiple allergy testing kits.