Simultaneous forward and reverse ABO blood group typing using a paper-based device and barcode-like interpretation.

A new platform of a paper-based analytical device (PAD) for simultaneous forward and reverse ABO blood group typing has been reported. This platform can overcome the discrepancy results as influenced by the individual haematocrit. The test and the control of non-haemagglutination on each channel were performed in parallel. The PAD was fabricated by printing six parallel channels with wax onto Whatman No. 4 filter paper. An LF1 blood separation membrane was used for the separation of plasma from whole blood for reverse grouping. The blood group was identified by haemagglutination of the corresponding antigen-antibody. For forward grouping, Anti-A, -B and -A,B were treated on the test line of PAD, and inactivated Anti-A, -B and -A,B were immobilized on the control line. For reverse grouping, 30% standard A-cells, B- and O- were added to the test channel after plasma separation, and O-cells were used as a control. Then, 0.9% normal saline (NSS) containing 1% Tween-20 was bi-functionally used for dilution of the blood sample and elution of the non-agglutinated RBCs within the channels. The distance of agglutinated RBCs in each test line was compared with the distance of non-agglutinated RBCs in the parallel control line. The forward and reverse patterns of blood groups A, B, AB and O were a barcode-like chart in which the results can be visually analysed. The PAD has excellent reproducibility when 10 replications of the A, B, AB or O blood groups were performed. The results of both forward and reverse grouping were highly correlated with conventional methods compared with the slide method and tube method, respectively (n = 76). Thus, this ABO typing PAD holds great potential for future applications in blood typing point-of-care testing.