Blood bankers do weird things, like mix antibodies with odd bodily fluids and infectious agents. Another strange thing we do is experiment with extracts from various seeds, because somewhere along the way, someone figured out that these extracts, called lectins, had antibody-like activity. Dolichos biflorus is the most famous of these lectins. It is most often used to distinguish the two main subgroups of blood group A: A₁ and A₂. Dolichos acts as an anti-A₁ reagent, meaning that at the dilutions we use it in the blood bank, it will agglutinate red cells that are of the more common A₁ subtype, distinguishing them from the less common A₂ subtype. This is useful in the workup of an ABO discrepancy caused by a group A₂ person making an anti-A₁leading to an unexpected reaction in ABO serum grouping. That scenario happens in less than 10% of A₂ individuals but 25% of A₂B persons. Dolichos may also be useful in the workup of polyagglutination.