Combination of magnetic beads extraction and ultraperformance liquid chromatography tandem mass spectrometry detection for the clinical diagnosis of allergies.

The total amount of immunoglobulin E (IgE) in human serum is an important parameter in diagnosing allergies. To reduce the false diagnosis of allergies and better assist in therapy, clinical studies can be performed to obtain accurate and reliable measurements of IgE. A magnetic beads (MBs)-based ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for total IgE measurement and the diagnosis of food allergies in serum was developed in this study. First, IgE was extracted by MBs coupled with anti-IgE antibody from serum. The extracted IgE was quantified by a specific signal peptide after digestion. A spiked linear IgE concentration ranging from 400 to 5000 ng mL was used for quantification. The limits of detection and quantification were 400 ng mL and 800 ng mL, respectively, for the developed method. Additionally, the combined capacity of the extracted IgE with different allergic proteins was evaluated by a binding experiment in vitro. The combining capacity of IgE with different allergens was used to speculate the kind of allergens that induce allergies in patients. Overall, a new method was developed that could be used to quantify the amount of IgE and simultaneously diagnose which allergen causes an allergic reaction, and this method may provide a powerful new tool in the clinical detection of allergies. Moreover, the developed method was applied to analyze IgE in four samples of patient serum and four serum samples from healthy individuals.