Quality control of hemoglobin solutions. I. The purity of hemoglobin before modification

It is not yet clear whether the toxicity of hemoglobin solutions is due to hemoglobin per se, contaminants, or both. To elucidate the problem, it is first necessary to prepare "pure hemoglobin," i.e., hemoglobin completely free of (a) bacterial endotoxins, (b) phospholipids of the red cell membrane, and (c) other proteins and/or peptides. The methods found most sensitive in the determination of such purity are here presented. Consensus on the adoption of these methods and on the meaning of the term "purity" would help to achieve (a) a better understanding of the toxicity problem, (b) a more meaningful exchange of information among investigators and (c) the ultimate development of nontoxic solutions.