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公司合作，开发一种简单，选择性但超敏感的电喷雾电离串联质谱（ESI-MS/MS）检测人类血液中的甲状腺激素。在新生儿筛查的背景下，甲状腺激素状况在临床实验室中被广泛测量，以及对各种影响人类健康和生活质量的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。目前，甲状腺激素是通过基于荧光的免疫测定法测量的，缺乏足够的选择性，导致偏倚和高假阳性率。目前迫切需要一种替代方法，以提高可靠性并降低临床常规甲状腺功能检测的操作成本。然而，由于其极低的浓度水平和固有的不稳定性，由于等离子体干扰导致离子抑制，通过ESI-MS/MS直接分析甲状腺激素具有挑战性。我们提出了一种改进的策略，用于游离和/或蛋白结合甲状腺激素的分析，基于一种新的直接注射前样品清理和灵敏度增强方案- esi -MS/MS。方法优化将在我们在麦克马斯特大学的实验室进行，然后在离子质谱上进行翻译，以进行后续验证。这个及时的项目将提供一种快速且具有成本效益的MS/MS技术的临床应用，用于甲状腺激素状态的常规诊断测试，而不需要低通量色谱分离，这将改善基于早期发现可治疗的甲状腺相关疾病的患者护理。

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.