Development and evaluation of a novel non-competitive MAGLUMI estradiol chemiluminescence immunoassay

Estradiol is a key estrogen, and measuring its circulating levels is essential for evaluating ovarian function, monitoring follicular development, and assessing reproductive health. In several patient samples, estradiol levels can be extremely low, surpassing the detection capabilities of current competitive immunoassays. This research introduces a non-competitive MAGLUMI estradiol chemiluminescence immunoassay (CLIA) that utilizes a two-step sandwich approach to quantify estradiol levels. The sandwich-based detection system for estradiol was established by preparing monoclonal antibodies for estradiol-primary antibody immune complexes. To optimize the performance of the reagents, we screened the ideal feeding ratios of the primary antibody to magnetic beads and the secondary antibody to ABEI, and then determined the best reaction system. The novel system exhibited higher sensitivity and precision compared to competitive assays. Besides superiority in limit of blank (LoB, 1.0 × 10⁻³ μg/L), limit of detection (LoD, 5.0 × 10⁻³ μg/L), limit of quantification (LoQ, 9.3 × 10⁻³ μg/L) and coefficient of variation for reproducibility (CV, 3.15 %∼9.47 %). The cross-reactivity with estrone, estriol, fulvestrant, abemaciclib and estradiol valerate is notably minimized. Meanwhile, the quantification result of this system strongly correlates with LC-MS/MS (y = 1.008x + 0.8949, R² = 0.981). In conclusion, the non-competitive reagents developed in this study for estradiol detection outperform existing competitive reagents, providing more reliable results for clinical applications.