Automatic measurement of the red cell oxygen dissociation curve identical with the whole blood curve

Automatic measurement of the entire oxygen dissociation curve (ODC) of bloo d and hemoglobin provides a useful means for evaluating their gas-transport function. The automatic oxygenation apparatus previously developed by Imai ef al, (1970, 1981), which uses a polarographic determination of partial p ressure of oxygen and a spectrophotometric determination of oxygen saturati on of hemoglobin, has mostly been used for the measurement of accurate ODCs of hemoglobin solution. However, it was not suitable for red cell suspensi on because a significant noise was superimposed on the absorbance signal du e to light-scattering by red cells, In the present study, we have overcome this problem by using an integrating sphere for the photometric system. Thr ough extensive tests we found the optimal experimental conditions for obtai ning the red cell oxygenation data that were identical with the whole blood data with respect to the position (oxygen affinity) and shape (sigmoid cha racter) of the ODC and its pH-dependence (the Bohr effect). The accuracy wa s higher than that of commercially available automatic apparatuses such as the "Hemox-Analyzer" (Technical Consulting Service) and "Hem-O-Scan" (Aminc o), Thus, our method provides an easy and convenient means for obtaining ac curate ODCs mimicking the whole blood ODCs from one drop of whole blood. An application of our method to the effect of blood storage on ODC is present ed, demonstrating the usefulness of our method.