B-044 Development and Evaluation of an Assay for the Detection of Human Total IgE in Serum on the Fully Automated Chemiluminescence Immunoassay Platform - Autolumo® 2000 Plus Analyzer
Authors: Yang X , Xi I , Zhang M , Zhu K , Li Z , Lee C 
Published: October 2024

Abstract

Background
The escalating prevalence of allergic diseases on a global scale, affecting approximately 20% of the world’s population, has become a significant health concern. Clinical determination of total IgE in serum and plasma is used as an aid to the diagnosis of allergic diseases. The tIgE CLIA Microparticles Kit is a chemiluminescent microparticle immunoassay for the quantitative determination of total IgE concentrations in human serum. This kit, integrated with the AutoLumo® 2000 Plus Analyzer, offers an automated, cutting-edge platform for total IgE detection. This streamlined combination provides clinicians with a reliable tool for comprehensive and efficient allergic diseases diagnosis.

Methods
The performance of tIgE CLIA Microparticles Kit was evaluated on AutoLumo® A2000 Plus automated chemiluminescence analyzer and compared to a well-characterized platform (Elecsys IgE II on Cobas e601, Roche). This assay is based upon the two-step sandwich method. During detection, the patient sample and the anti-IgE coated microparticles solution were added sequentially. Unbound components were washed off after incubation. The formation of a complex occurred with the subsequent addition of a HRP conjugated anti-IgE antibody solution. The catalysis of chemiluminescent substrates by this complex generated a measurable light signal recorded as RLUs (Relative Light Units). A 2-point calibrator was used to analyze the tIgE antibody concentrations in the serum sample. The limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), accuracy, repeatability, linearity, specificity, on-board stability and real-time stability of the assay kit were evaluated. Serum samples (n=220) that had been previously well characterized were used for method comparisons.

Results
The tIgE CLIA Microparticles assay demonstrated a measurement range of 5-2500 IU/mL, with LoB, LoD, and LoQ values of ≤3 IU/mL, ≤4 IU/mL, and ≤5 IU/mL, respectively. The accuracy of the assay kit was assessed by trueness and precision following CLSI EP15-A2 and EP5-A2 guidelines. The trueness was evaluated using WHO IRP 11/234 as the reference standard, the estimate %bias between the expected and measured mean value was ≤5%. The average %CV of the intra-run and inter-run precision were 5.00% and 3.24% respectively, with a linearity of R≥0.990. The specificity to tIgE is evident, with no cross-reactivity to IgA, IgG, and IgM (≤100 μg/mL), and minimal interference from rheumatoid factor (RF) and anti-nuclear antibodies (ANA) (&lt;10%). Furthermore, based on the CLSI EP7-A2 guideline, it showed no endogenous interference with bilirubin (30 mg/dL), hemoglobin (250 mg/dL), and triglycerides (3000 mg/dL) and no exogenous interferences with 14 commonly used allergy treatment drugs except Omalizumab (360μg/mL). Notably, the assay remains stable on-board for 28 days and exhibits real-time stability for up to 12 months at 2-8ᵒC. Clinical evaluation, involving 220 samples covering the linearity range of 5.0-2500 IU/mL, reveals a strong correlation (R&gt;0.990) and the bias was within 15% when compared to a reference kit according to the CLSI EP9-A2 guideline.

Conclusions
Autolumo® Analyzers, in conjunction with the tIgE CLIA Microparticles Assay, presents a fully automated chemiluminescence immunoassay platform for accurate and cost-effective screening to aid allergic diseases diagnostics with excellent specificity, precision, and on-board stability.