Lot-to-Lot Reproducibility of Standardized Allergen Extracts in IgE In Vitro Diagnostic Tests

Abstract

In the United States, standardized allergen extracts are commonly used for immunotherapy and skin prick testing to reduce variability and improve consistency of results. These extracts are biochemically and analytically characterized to identify clinically relevant allergens. With about half of non-standardized extracts lacking any evidence of efficacy, standardization ensures uniform allergenic potency across manufacturers and across individual lots. Ideally, this improved potency in standardized extracts can also offer value to IVD testing. In this study, we evaluate lot-to-lot reproducibility of specific IgE (sIgE) test results when utilizing standardized allergen extracts. Three lots of D001 (D. pteronyssinus, House Dust Mite), E001 (Cat Dander), and G006 (Timothy Grass) standardized extracts were acquired from two allergen manufacturers and subsequently evaluated using several analytical techniques (SDS, Western Blot, and HPLC). Each extract lot was then biotinylated, placed on the NOVEOS™ Immunoanalyzer, and tested for the presence of sIgE across a panel of known sensitized and negatives patients for each allergen. All lots for each allergen exhibited similar protein profiles with identifiable allergenic determinants. Sensitivity and specificity were consistent across lots and minimal bias was observed when tested on the NOVEOS Immunoanalyzer. Utilizing standardized extracts in sIgE IVD tests can result in reliable and consistent results and may offer additional value compared to traditional crude extracts. When standardized extracts are not available, allergen characterization should be performed in order to ensure only high quality extracts containing the comprehensive spectrum of IgE-binding molecules are used.