Despite significantly improved diagnostics and therapeutic advancements for MG patients, biomarkers to predict or individually tailor medications still need to be developed. This chapter provides an update on objective biomarkers, focusing on blood and digital measures that could be used for diagnostic and monitoring purposes for MG patients. Novel predictive biomarkers could significantly enhance patient stratification and inform treatment decisions.

Biomarkers are measurable indicators to assess physiological or pathological processes or responses to exposures or therapeutic interventions (Group, 2016, Health,). Based on their function or specific purpose, biomarkers can be classified into seven categories (Table 1). A single biomarker can serve multiple purposes and fall into two or more categories.

Blood biomarkers include cells, proteins, metabolites, or small non-coding RNA involved in the autoimmune response, a hallmark of MG. Digital biomarkers are under development to enhance the monitoring of patients outside the usual clinical setting using home-based connected products such as wearables and sensors (Izmailova et al., 2023). A well-validated biomarker can be invaluable in research and clinical practice, providing critical insights that enhance the understanding of underlying chronic disease processes, early sensitive diagnosis, and treatment response. The heightened rigor and ongoing advances in understanding pathophysiology and the application of state-of-the-art technology will lead to the identification of biomarkers that will offer objective metrics to enhance diagnosis, select treatment, and monitor patients with MG.