Application of an Automatic Oxygenation Technique to Analysis of Oxygen Equilibrium Curves for Hemoglobinopathy Red Cells and Functional Screening of Clinically Important Hemoglobinopathies

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Abstract
The automatic oxygenation technique of Imai et al was slightly modified and applied to the study of O2 equilibrium curves of dilute, red cell [RBC] suspensions from normal subjects and individuals with hemoglobinopathies, enzymopathies and other hematologic disorders. The p50 [partial pressure at 50% saturation] values of non-smoking, normal adults were 25.9 .+-. 0.6 mm Hg at pH 7.4 and 37.degree. C, and corresponded to values for whole blood reported in the literature. O2 equilibrium curves of suspensions from subjects with enzymopathies revealed shifts in position which were throught to be due to alterations in the concentration of 2,3-DPG [2,3-diphosphoglycerate] of the RBC. Abnormalities in shape of the equilibrium curves were observed only for the hemoglobinopathic RBC, and could best be illustrated by the abnormally low Hill''s exponent (n*). Analyses of the n* values of 34 patients with various RBC disorders of unknown causes led to identification of 10 cases showing low values. In 5 of the 10 patients, presence of an abnormal Hb was confirmed using column chromatography on Amberlite CG-50. These results point to the usefulness of the Hill Plot analysis of RBC O2 dissociation curves in functional screening for clinically important hemoglobinopathies.