The comment of Dr Kane is certainly pertinent. As indicated in our article, the observation of increased hematocrit value, RBC count, and hemoglobin concentration after parathyroidectomy (PTx) was made by a retrospective study.
Unfortunately, RBC mass was not determined systematically in these patients. Hydration state in hemodialyzed patients changes from day to day, but it is unlikely that hemodilution prior to PTx was different from that six to 12 months later in all patients studied. This statement is supported by our finding that no substantial difference was noted when comparing the values of plasma total protein concentration before and six months to one year after PTx. The mechanism of the influence of hyperparathyroidism on amemia may be multifactorial. Recently, an in vitro study favored a direct toxic inhibitory effect of excess parathyroid hormone on erythropoiesis.1 Regression of marrow fibrosis may be involved only in the patients with initially abundant