Studies on Clot Density

Abstract

The clot density constitutes the difference of the optical densities of plasma before and after clotting, as read from the optical density scale of the Coleman Spectrophotometer during the course of the prothrombin detn., as carried out with the photoelectric modification of the one-stage Quick method. It is constant for each sample of plasma and was found to be directly proportional to its fibrinogen concn. A comparison of the clot density with the corrected sedimentation rate in over 1300 random blood samples revealed a general correlation between the 2 detns. A comparison of the clot density with the corrected sedimentation rate in 80 acutely and chronically ill patients performed consecutively every other day for periods from 2 wks. to 3 mos. revealed a similar pattern for both tests. The clot density generally shows less fluctuation and in several instances reflected the course of the disease process more closely than the sedimentation rate. The clot density appears to be of particular practical value in patients undergoing treatment with dicumarol.