Artifactual hypoglycemia associated with hematopoietic cytokines

We observed apparent hypoglycemia in seven patients manifesting granulocytosis associated with hematopoietic cytokine treatment or with a leukemoid reaction. All seven patients had confounding preanalytic conditions of specimen transport delay and lack of antiglycolytic agents. Cytokine-stimulated leukocytes may cause artifactual hypoglycemia by consuming glucose in vitro, possibly leading to unnecessary diagnostic evaluation. The glucose depletion was faster in blood drawn from patients receiving granulocyte colony-stimulating factor (0.29 mmol/L/h) than in blood from a control group (0.17 mmol/L/h) or from a group with leukemia (0.23 mmol/L/h). Stabilization with sodium fluoride (60 mmol/L) slowed the glucose depletion in both the cytokine group (0.13 mmol/L/h) and the leukemic group (0.09 mmol/L/h), which were then statistically indistinguishable from the control rate (0.10 mmol/L/h). In blood obtained from patients being treated with hematopoietic cytokines or who have leukemoid reactions, an antiglycolytic agent should be used whenever separation of plasma might be delayed more than 1 hour.