Delgado Jose Antonio, Pastor García María I, Jiménez Nuria Márquez, Petit Gemma Costa, Pablo Cànaves Josep A, Robles Juan, Bauça Josep Miquel
Department of Laboratory Medicine, Hospital Universitari Son Espases, Palma, Spain.
Department of Laboratory Medicine, Hospital Universitari Son Espases, Palma, Spain.
Clin Chim Acta. 2023 Feb 15;541:117267. doi: 10.1016/j.cca.2023.117267. Epub 2023 Feb 18.
BACKGROUND-AIM: High vitamin B12 concentrations are considered a common finding in clinical practice. Thanks to immunoassay accessibility, vitamin B12 has become a usual test in routine health checkups. However, these analytical methods usually present antibody-mediated interferences. Our aim was to propose an algorithm for the screening of antibody-mediated analytical interferences on vitamin B12 immunoassays on the Alinity platform.
Observational, prospective, case-control study was performed during 12 months. Individuals with persistently elevated cobalamin concentrations [>554 pmol/L] were considered as cases in the absence of supplementation or other justifying cause. Individuals under treatment with vitamin B12, or in the context of alcoholism were included as controls. A thorough interference study by macromolecules in immunoassays was performed in serum samples: PEG precipitation, rheumatoid factor, heterophile antibodies and gel permeation chromatography (GPC). Albumin, total B12, IgG and IgM were measured in every GPC collected fraction and chromatograms were drafted.
Up to 45% of cases presented interference by B12-immunocomplexes and the precipitation for all of them was >50%. The individual with the lowest interfered vitamin B12 result was 661 pmol/L.
The presence of antibody-mediated interferences, mainly B12-immunocomplexes, is a relatively common phenomenon. A simple algorithm for the screening of interferences is useful and reliable in ruling out healthy individuals and highly cost-effective.
高维生素B12浓度在临床实践中被认为是常见发现。由于免疫测定易于进行，维生素B12已成为常规健康检查中的一项常见检测项目。然而，这些分析方法通常存在抗体介导的干扰。我们的目的是提出一种算法，用于筛查Alinity平台上维生素B12免疫测定中抗体介导的分析干扰。
进行了为期12个月的观察性、前瞻性病例对照研究。钴胺素浓度持续升高[>554 pmol/L]且未补充维生素B12或无其他合理解释原因的个体被视为病例。接受维生素B12治疗的个体或酗酒个体被纳入对照组。对血清样本进行了免疫测定中大分子的全面干扰研究：聚乙二醇沉淀、类风湿因子、嗜异性抗体和凝胶渗透色谱法（GPC）。在每个收集的GPC级分中测量白蛋白、总B12、IgG和IgM，并绘制色谱图。
高达45%的病例存在B12免疫复合物干扰，且所有病例的沉淀率均>50%。维生素B12受干扰结果最低的个体为661 pmol/L。
抗体介导的干扰，主要是B12免疫复合物的存在是一种相对常见的现象。一种简单的干扰筛查算法在排除健康个体方面有用且可靠，并且具有很高的成本效益。
