Comparison between specific IgE measured by RAST, two chemiluminescent assays and skin prick test

Area of Science:

• Allergy diagnostics
• Immunology
• In vitro diagnostics

Background:

• Accurate measurement of specific IgE is crucial for diagnosing allergic diseases.
• Multiple in vitro assays exist, but their performance, especially in low-level detection, can vary.
• Comparison of classical radioallergosorbent assay (RAST), chemiluminescent assay (CLA), and immunocheminometric assay (MAGIC LITE SQ) against skin prick testing (SPT) is needed.

Purpose of the Study:

• To compare the performance of three different specific IgE assays: Phadebas RAST (P-RAST), chemiluminescent assay (CLA), and MAGIC LITE SQ (ML).
• To evaluate the correlation between these assays and skin prick testing (SPT).
• To assess assay sensitivity, particularly in detecting low levels of specific IgE.

Main Methods:

• Two hundred adult allergy patients underwent skin prick testing (SPT) with standardized allergen extracts.
• Specific IgE levels against ten inhalant allergens were measured using P-RAST, CLA, and ML assays.
• Data analysis included frequency distribution, Kendall's rank correlation, and Pearson correlation coefficients.

Main Results:

• Significant differences in specific IgE detection rates were observed: P-RAST (17%), CLA (66%), ML (17%).
• CLA demonstrated a U-shaped distribution, indicating higher sensitivity in detecting both very low and high IgE levels compared to P-RAST and ML.
• High correlations were found between CLA and SPT (r=0.65), including in the low-level IgE subgroup (r=0.60).

Conclusions:

• Marked discrepancies exist between the three specific IgE assays evaluated.
• The CLA system appears more sensitive than P-RAST and ML, especially for low-level specific IgE.
• Further clinical studies are warranted to determine the clinical utility of CLA's enhanced sensitivity.