American Society of Plastic Surgeons. This is an open-access

Bone marrow aspirates can be used in therapies to treat ischemic tissues, bone fractures, and bony defects. These treatments primarily uti- lize 2 methods.1–8 The first involves transplantation of marrow mononuclear cells isolated from aspirates using density gradient centrifugation or a cell sepa-rator. The second method involves isolation and culture of bone marrow–derived endothelial pro-genitor cells or mesenchymal cells. The disadvantag-es of these methods are the time requirements and safety issues arising from the use of animal-derived materials in culturing or the need for chemicals that are not usually used for clinical applications. Red blood cells may be removed by erythrocyte sed-imentation9 using a hemagglutination reagent or by hemolysis using ammonium chloride. We speculated that if efficient hypo-osmotic lysis of just the red blood cell fraction could be performed using distilled water, which is readily available and harmless to the human body, then such a method could be easily adapted fo