Effect of agglutinating substances on optical density of blood in vitro and in vivo.

Abstract

The optical density (OD) of canine blood (densitometer, 800 m[mu]) decreased with increasing concentration or degree of polymerization of added polybasic polymers. Sedimentation rate studies indicated that this OD change was related to size of the aggregates formed. Whereas the spectral transmission of blood-dye or blood-hypertonic NaCl mixtures stabilized in less than 10 sec, that of the blood-polymer mixtures failed to stabilize in 60 sec. Injection of polybasic polymers or 20% NaCl into the right ventricle of dogs with sampling of the blood-medium mixture simultaneously from pulmonary artery, left atrium, and femoral artery suggested pulmonary trapping of red cell aggregates, which was confirmed by hematocrit and hemoglobin determinations of left atrial blood samples. Such trapping plus crenation of red cells were believed to cause the diphasic OD changes recorded following 20% NaCl injection. Measurement of the OD of blood offers a simple sensitive technique for detecting red cell aggregation in vitro and in vivo.