Measurement of the electric resistance of human blood; use in coagulation studies and cell volume determinations.

Abstract

Abstract A reliable rapid method for the measurement of electric resistance of small amounts of blood or similar material is presented. A pattern of change in the resistance of blood during coagulation is described. These resistance changes make possible the determination of the clotting time with elimination of inconsistencies caused by motion and offer a quantitative means for the study of clot retraction. In view of the fact that no method has been available previously for a comparable quantitative study of clot retraction, electric resistance measurements may serve to detect significant variations of this process in disease beyond our present knowledge. By means of the ratio of blood resistance to plasma resistance, the cell volume fraction of a sample of blood may be calculated. Cell volumes determined by resistance measurements were found to average 7.7 per cent lower than the hematocrit as determined by centrifugation.