GYPA and COVID-19: Although RBC counts and hemoglobin levels have been evaluated in COVID-19 patients, there is limited information on the direct effect of SARS-CoV-2 infection on erythropoiesis, erythroid progenitors, and RBC structural proteins such as CD235a [cluster of differentiation 235a], and CD36.10 Erythroid progenitors are defined as CD71+ and CD235a+.