olyHeme® is a solution of chemically modified hemoglobin derived from human blood. Hemoglobin is the oxygen-carrying component of the human red blood cell. Northfield purchases donated blood from The American Red Cross and Blood Centers of America for use as the starting material for PolyHeme. The company uses a proprietary process of separation, filtration and chemical modification to produce PolyHeme. Hemoglobin is first extracted from red blood cells and filtered to remove impurities. The purified hemoglobin is next chemically modified using a multi-step process to create a polymerized form of hemoglobin designed to avoid the undesirable effects historically associated with hemoglobin-based blood substitutes, including vasoconstriction, kidney dysfunction, liver dysfunction and gastrointestinal distress. The modified hemoglobin is then incorporated into a solution which can be administered as an alternative to transfused blood. One unit of PolyHeme contains 50 grams of modified hemoglobin, approximately the same amount of hemoglobin delivered by one unit of transfused blood.