A practical starting guide to tear fluid biobanking.

Background: Tear fluid is increasingly recognized as a minimally invasive source of biomarkers in various diseases with broad potential for diagnostics and disease monitoring. Biobanking tear fluid samples provides valuable access to high-quality biological samples while reducing the need for new collection efforts. Ensuring appropriate collection and storage conditions is critical for maintaining sample integrity. However, standardized guidelines and operating protocols for tear fluid biobanking are still lacking. Main text: This review synthesizes existing literature on tear fluid biobanking, complemented by additional sources such as reports and online guidelines on biobanking standards and recommendations. Together, these insights provide a practical guide for researchers and institutions aiming to establish a tear fluid biobank or integrate tear fluid samples into existing biobanking infrastructures. This guide outlines key aspects including (i) governance, regulatory, and ethical considerations, (ii) biosafety, infrastructure, and logistics, (iii) collection methods and materials, and (iv) data harmonization through the developed and proposed Tear Fluid-Common Data Elements, which emphasize on the collection, storage, processing, and analysis of biobanked samples. Conclusions: By providing clear and practical guidance, this review supports the standardization of tear fluid biobanking, thereby enhancing the value of these samples for future research and clinical applications.