HYCOR White Papers
CCD Interference in Allergy Testing:
Why Laboratorians Should Worry
For clinical laboratories using ImmunoCAP testing (i.e. use Phadia instruments from Thermo Fisher Scientific)
The Pain Point:
False positive specific IgE results across various important allergen groups such as peanut, venoms, grasses and others. Reflex testing based on a positive will lead to excess testing and costs.
Take away points:
Cross-reactive carbohydrate determinants (CCDs). In vitro allergy testing is used as an aid in diagnosis of allergic disease. False positive or elevated results due to non-specific binding of CCD in the assay are misleading and may interfere with proper diagnosis, require additional diagnostic testing or unnecessary treatment, and cause undue stress to patients.
A population of 236 samples tested on the Phadia and NOVEOS systems using CCD-free components and in the presence (filled circles) or absence (open circles) of CCD inhibitors.
Red arrows designate samples false positive results on the Phadia system. The data suggests that samples near the cutoff of 0.35 are affected and generate false positive values that can be misleading.
Assays were tested using CCD-free peanut components suggesting that the change in reactivity in the presence of a CCD inhibitor was due to reactivity to the assay solid phase rather than any interaction with the proteins themselves.