<p>This review presents a comprehensive overview of the emerging field of lab-on-paper diagnostics, with a specific focus on blood analysis, underscoring their significance as low-cost, portable, and effective solutions for point-of-care testing in resource-constrained environments. It highlights the novel integration of microfluidic principles on paper substrates, enabling decentralized testing and minimizing reliance on centralized laboratory infrastructure. The review outlines recent technological advancements in device fabrication—such as wax printing, laser cutting, and 2D/3D structural designs—as well as innovative fluid control mechanisms and detection strategies including colorimetry, electrochemical sensing, and fluorescence. A key emphasis is placed on the incorporation of complex, on-chip sample pretreatment processes like plasma separation and analyte concentration, which represent a significant step forward in making lab-on-paper devices suitable for real-world blood diagnostics. Additionally, the work explores the capability of these platforms to detect a wide range of blood-borne biomarkers, highlighting their potential to bridge healthcare gaps globally. While acknowledging current challenges—such as material durability, environmental resilience, and digital integration—this review identifies critical future directions that could drive the widespread adoption and impact of lab-on-paper systems. The work showcases the transformative potential and growing relevance of paper-based diagnostics in achieving equitable and accessible healthcare.</p> Graphical Abstract <p></p>