Hemoglobin is a fraction of a red blood cell. However it makes up 33% of a red blood cell and basically is responsible for the function of a red blood cell. PolyHeme is human hemoglobin that has been chemically modified and purified using a multi-step process to create a polymerized form of hemoglobin. Most who accept fractions over primary components accept minor fractions, and therefore may have a problem with a product that makes up 1/3 of a primary component. Any fraction that is not recombinant or heat processed has the potential (although very small) for disease transmission.