The most widely known blood groups, ABO and
RhD, have been extensively observed as having strong
antibody-antigen interactions during blood typing. However,
not all interactions show the same binding affinity. The Duffy
blood group system, where Fy a and Fy b antigens are the most
clinically significant, are only available with an IgG antibody
structure, and display weak binding interactions. While cur-
rent blood typing techniques are well established, methods for
quantifying the binding strength are more limited. Surface
Plasmon Resonance (SPR) provides avenues for developing
more robust detection methods, and serve as a sensitive quan-
tification technique by itself. This study tested SPR for the
detection of weaker antibody-antigen interactions using the
Duffy blood groups, Fy a and Fy b , as a model. This study
shows a minimum threshold of antibody concentration is re-
quired for successful detection. Some instances of detection
were successful using concentrated commercial anti-Fy a and
anti-Fy b solution during the incubation stage. However, these
results were not fully reproducible. We found that a significant
dissociation of the Duffy antigen-antibody complex occurs
over time. A combination of factors affects the detection of
the Duffy antigens using SPR; these include antibody concen-
tration, antigen expression, and antigen structure. This results

• Duffy blood group (Fy a & Fy b ) analysis using surface plasmon resonance