© 2016 AABB BACKGROUND: Hydroxyethyl starch (HES) is reportedly associated with an increased risk of renal failure and death when used for fluid resuscitation in critically ill patients. HES can be used during therapeutic leukocytapheresis (TL) procedures to enhance cell separation. The purpose of this study was to evaluate the occurrence of adverse events associated with HES during TL procedures. STUDY DESIGN AND METHODS: We performed a retrospective review of patients who underwent TL with and without HES in the period 2009 to 2013 at six academic medical institutions. RESULTS: A difference-in-difference regression analysis was used to estimate the mean change before and after TL in selected outcomes in the HES group relative to the average change in the non-HES group. Selected outcomes included serum creatinine, estimated glomerular filtration rate (eGFR), and white blood cell (WBC) count. A total of 195 patients who underwent 278 TL procedures were studied. We found no significant differences in serum creatinine levels and eGFR on Days 1 and 7 after TL procedure between patients who received and those who did not receive HES. The rate of adverse events and overall and early mortality were similar in both groups. Patients with acute myeloid leukemia who received HES had greater WBC reduction when HES was used. Additionally, patients who received HES had improvement in pulmonary leukostasis symptoms. CONCLUSION: HES, used at low doses during TL procedures, was not associated with adverse events previously ascribed to its use as a volume expander.