CD34+ cell collection efficiency does not correlate with the pre-leukapheresis hematocrit

One hundred and seventy-seven large-volume leukapheresis procedures performed on 91 patients over a 15 month period were reviewed to see if the pre-apheresis hematocrit (Hct) affected the CD34+ cell collection efficiency (CE) of the Fenwal CS 3000 Plus cell separator. The Hct was 0.174–0.461 (median 0.317), and the peripheral blood CD34+ cell count 2–2487 per μl (median 21). The total CD34+ cell quantity collected was 3.0–2677.2 × 106 (median 113.0). Based on the number of CD34+cells contained in the blood volume processed (23.3–37303.2 × 106; median 318.0), the CE was 1.7–87.5% (median 30.3). No correlation was found between the Hct and CE (r2 = 0.0034; P = 0.44) or the total CD34+ cell quantity collected (r2 = 0.0040; P = 0.40). CEs for Hct <0.25 (median CE 36%), Hct 0.25–0.299 (median CE 30%) and Hct 0.30 (median CE 30%) were comparable. As expected, highly significant correlations were seen between the CD34+ cell quantities collected and quantities processed (r2 = 0.59; P < 10−6) as well as the peripheral blood CD34+ cell counts (r2 = 0.60; P < 10−6). We conclude that the minimum acceptable Hct or hemoglobin level for leukapheresis should be dictated by clinical circumstances because it does not affect stem cell collection. Bone Marrow Transplantation (2001) 28, 597–601.