Assay for thyroid hormone diagnostics by direct injection-tandem mass spectrometry

该项目旨在与加拿大当地仪器制造商离子质谱仪合作，开发一种简单、选择性和超灵敏的分析方法，通过电喷雾电离串联质谱仪(ESI-MS/MS)测定人体血液中的甲状腺激素。在影响人类健康和生活质量的各种获得性甲状腺相关疾病(如甲状腺功能减退症)的诊断测试和治疗监测的背景下，临床实验室广泛测量甲状腺激素状况。目前，甲状腺激素的测定是基于荧光的免疫分析，缺乏足够的选择性，导致偏差和高的假阳性率。迫切需要在临床环境中对甲状腺功能常规检测提供更高的可靠性和更低的操作成本的替代方法。然而，由于其极低的浓度水平和固有的不稳定性，直接用ESI-MS/MS分析甲状腺激素是一项挑战，因为血浆干扰会导致离子抑制。我们建议引入一种改进的策略，在直接注射-ESI-MS/MS之前，基于一种新的样品清理和灵敏度增强协议，对游离和/或蛋白质结合的甲状腺激素分析进行改进。方法优化将在我们位于麦克马斯特大学的实验室进行，然后在离子质谱仪进行翻译，以进行后续验证。这一及时的项目将提供快速且经济高效的MS/MS技术的临床应用，用于甲状腺激素状况的常规诊断测试，而不需要低通量的层析分离，这将在早期发现可治疗的甲状腺相关疾病的基础上改善患者护理。

This project aims to develop a simple, selective yet ultra-sensitive assay to measure thyroid hormones in human blood by electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in partnership with a local Canadian instrument manufacturer, Ionics Mass Spectrometry. Thyroid hormone status is widely measured in clinical laboratories in the context of newborn screening, as well as diagnostic testing and treatment monitoring of various acquired thyroid related-diseases (e.g., hypothyroidism) that impact human health and quality of life. Currently, thyroid hormones are measured by fluorescence-based immunoassays that lack adequate selectivity resulting in bias and high rates of false-positives. There is an urgent need for alternative methods that offer improved reliability and lower operating costs for routine testing of thyroid function in a clinical setting. However, due to its extremely low concentration levels and inherent instability, direct analysis of thyroid hormones by ESI-MS/MS is challenging due to plasma interferences that result in ion suppression. We propose to introduce an improved strategy for free and/or protein-bound thyroid hormone analysis based on a novel sample cleanup and sensitivity enhancement protocol prior to direct injection-ESI-MS/MS. Method optimization will take place in our laboratory at McMaster University followed by its translation at Ionics Mass Spectrometry for subsequent validation. This timely project will provide a rapid yet cost-effective clinical application of MS/MS technology for routine diagnostic testing of thyroxine hormone status without low throughput chromatographic separations that will improve patient care based on early detection of treatable thyroid related-disorders.