Elution studies are performed to separate bound Ig from a patient’s RBCs in the setting of an IgG-positive DAT; this separation is typically accomplished using pH or temperature changes. As depicted, the eluates from COVID-19 patients with an IgG-positive DAT did not show agglutination after incubation with commercially available reagent RBCs. However, the same eluates incubated with RBCs derived from other COVID-19 patients showed agglutination. Professional illustration by Patrick Lane, ScEYEnce Studios. AHG, anti-human globulin.