Establishment of Flow Cytometry-Based Assay for the Quantitative Measurement of Erythrocyte Agglutination in Clinical Laboratory

This study explores a novel sensitive and accurate method for the quantitative determination of red blood cells (RBCs) agglutination in clinical laboratory. Natural antibodies (Anti-B) were selected and diluted as 1:2, 1:4,1:8 and 1:16 to react with healthy blood group RBC-B, using normal saline as a control group. All the sample tubes were incubated at 37 °C for 30 min. On other hand, tube method was also used and the degree of agglutination was graded. The strongest agglutination was observed in the 1:1 dilution, but as the serum was serially diluted from 1:2 to 1:16, the agglutination strength decreased. In contrast, no agglutination was found in the control group. Furthermore, we plotted the logarithm of serum dilution on X-axis coordinate while the index of agglutination (IAG) on Y-axis coordinate, which showed that there is a good linear relationship existed between IAG and serum (Anti-B) Concentration (r = 0.979 and P = 0.004). A serum stability test conducted over 10 consecutive days showed a coefficient of variation (CV) of 2.26%, indicating good stability of the test results. Our study concluded that the flow cytometry method (FCM) was most reliable, accurate and sensitive tool for the detection of RBCs agglutination in clinical settings.