AbstractThe variability in the clinical expression of sickle cell anemia led us to study factors which might influence the course of this disease. We examined erythrokinetics, blood volumes, and variables which influence hemoglobin function in a group of adults with sickle cell anemia of varying degrees of clinical severity. We were unable to correlate any single measurement with the clinical course; however, our patient sample was small and the data suggested areas for further study. An expansion of plasma volume was noted in all patients. This made it difficult to predict red cell mass from the hemoglobin level, which consistently underestimated its magnitude. The red cell production index and iron turnover values indicated that there is often a suboptimal erythropoietic response to anemia in sickle cell disease.