Rapid and Cost-Effective ABO Blood Genotyping Using a Freeze-Dried, Point-of-Care Ready Loop-Mediated Isothermal Amplification (LAMP) Assay

<b>Background:</b> The accurate and rapid genotyping of <i>ABO (chromosome 9q34.2)</i> blood types is critical for clinical diagnostics and transfusion medicine, particularly in scenarios where serological methods yield uncertain results, such as in neonatal testing or with rare <i>ABO</i> subtypes. <b>Methods:</b> This study describes a loop-mediated isothermal amplification (LAMP)-based method for <i>ABO</i> genotyping that offers a faster and more cost-effective alternative to conventional PCR-based techniques. <b>Results:</b> The method targets four key single nucleotide polymorphisms (SNPs) at positions 261, 297, 703, and 930, allowing for the differentiation of common A, B, and O blood types, as well as the rare AB subtype B(A)01. The detection of the B(A)01 subtype is clinically important for preventing transfusion mismatches where serology may be inconclusive. Operating at a constant temperature, the assay can be completed in under an hour without the need for a thermocycler, offering significant time and cost benefits over qPCR. The method demonstrated high specificity, demonstrating detection down to 10 copies across all assays. When validated against a gold-standard method on clinical blood samples, the LAMP assay showed high accuracy (95% C value calculated via binomial exact method): 97.4% for type O, 98.7% for type A, 98.7% for type B, and 100% for the B(A)01 subtype. To enhance usability for point-of-care applications, freeze-dried reagents were developed that permit direct loading of lysed blood samples while maintaining high performance. <b>Conclusions:</b> This simplified and robust format positions the LAMP assay as a promising tool for rapid and reliable <i>ABO</i> genotyping in diverse clinical settings.