Laboratory Medicine in Immune Checkpoint Inhibitor-Induced Autoimmune Disorders: Baseline Assessment, Diagnostic Algorithms, Monitoring, and Predictive Biomarkers

Immune checkpoint inhibitors (ICIs) have substantially improved clinical outcomes across multiple malignancies, but they can disrupt self-tolerance and induce immune-related adverse events resembling autoimmune disorders. In many cases, laboratory abnormalities precede overt clinical manifestations, placing laboratory medicine at the center of baseline evaluation, early recognition, diagnostic confirmation, longitudinal monitoring, and treatment follow-up. This review provides a laboratory-focused overview of ICI-induced autoimmune disorders, focusing on baseline laboratory assessment, monitoring strategies during therapy, organ-specific diagnostic algorithms, ICI-specific toxicity patterns, and candidate predictive biomarkers. Particular attention is paid to endocrine, hepatic, metabolic, cardiac, rheumatologic, and neurologic toxicities and to pre-analytical and analytical issues that can confound interpretation. The potential contribution of digital tools and artificial intelligence to accelerating laboratory-based detection is also discussed. Standardized laboratory pathways integrating baseline testing, reflex and confirmatory algorithms, trend-based surveillance, and multidisciplinary interpretation can improve safety and support personalized decisions regarding immunotherapy continuation and management.