Clinically relevant hypokalaemia, hypocalcaemia, and loss of hemoglobin and platelets during stem cell apheresis

Since the introduction of hematopoietic growth factors, the collection of mobilized stem cells via leukapheresis has widely replaced the harvest of bone marrow in both autologous and allogeneic transplantation settings. We investigated the frequency and the extent of anticoagulant-induced electrolyte changes and the cell-separation-related loss of hemoglobin and platelets. In our study a total of 200 leukaphereses were performed on 60 patients with hematological malignancies. The electrolytes (calcium and potassium) were determined photometrically pre- and post-apheresis. Blood counts were analyzed to calculate the relative decline in hemoglobin and platelet counts. Stem cells were collected by processing a mean total blood volume of 11.6+/-3.9 L with a citrate consumption of 1,345+/-126 mL. More than 50% of all patients needed replacement therapy of either potassium or calcium. In non-substituted patients the initial serum potassium concentration dropped by 11.3+/-7.0% to 3.25+/-0.33 mmol/L post apheresis. In 21% of non-substituted patients, clinical relevant hypokalaemia was observed with levels < 3 mmol/L. The mean citrate-induced reduction of the total calcium was 5.5+/-6.0%. In addition the relative loss of hemoglobin and platelet counts amounted to 10.7+/-5.2% and 24.2+/-12.5%, respectively. In addition to the well-documented citrate-induced hypocalcaemia, we observed a considerable reduction in serum potassium during stem cell apheresis. This can result in a clinically relevant, substitution requiring hypokalaemia. The modest decline in hemoglobin and platelet counts suggested that levels of >9 g/dl (Hb) and platelets >30 x 10(9)/L are sufficient for a safe standard leukapheresis.