Polymethyl methacrylate (PMMA) point of care for ABO-Rh(D) blood typing

Polymethyl methacrylate (PMMA) based point of care (POC) for ABO-Rh(D) blood grouping by the naked eye was investigated. PMMA substrate was covalently linked with carboxyl methyl dextran (CMD) and coupled to the blood group specific antibodies anti A, anti B, and anti D, which were patterned into “A”, “B”, and “+”. The red read out color originated from the color of hemoglobin in the RBCs. The major human blood group, ABO-Rh(D), was successfully sorted using these patterns. PMMA strip-based assays for blood grouping by the naked eye resulted in correct blood group identification of all 74 samples in comparison to slide agglutination test. The determination of captured RBC Rh(D) required a longer reaction time with immobilized anti D antibody on the PMMA substrate than other blood groups to produce sufficient color for unambiguous visual identification. The proper RBC concentration was found to be higher than 1% v/v for naked eye detection. The dilution of blood sample is playing a crucial role in reducing interference from blood proteins during detection. A used of undiluted blood sample for the testing should be avoided. The proper blood dilution was found to be 10% or 1:10 dilution. The proposed technique presents a quick, cheap, simple, and almost instantaneous assay for blood grouping.