Factors Influencing Sedimentation Rate of Erythrocytes

Abstract

There is increasing use of the sedimentation rate of erythrocytes as a test in clinical medicine, but there is equal difficulty in correct interpretation of the results obtained due to the many factors that influence it. Much work has been done to elucidate the value of this test in different clinical conditions, especially in infections.

Fahareus 1 has reviewed the literature and studied many of the factors that influence the sedimentation velocity of erythrocytes, especially the amount of fibrinogen and globulin in the plasma. Many other publications add new evidence. Westergren 2 , 3 states that a definite positive correlation exists between the plasma proteins and the sedimentation of erythrocytes. Zarday and Farkas 4 have modified blood by the addition of normal fibrinogen and globulin and found that the sedimentation rate was increased in proportion to the amounts added. When they added albumin the rate was decreased. Coburn and Kapp 5 arrived at similar conclusions and added that albumin inhibited sedimentation almost completely. Lucia and coworkers 6 , 7 , 8 , 9 found that in vitro a consistent relationship cannot be established between the sedimentation rate and the globulin content of various dilutions of serum globulin. They also showed that in vivo the sedimentation rate is apparently accelerated as the globulin content of the serum increases, and that a cause and effect relationship between the quantity of the various serum proteins and the rate of sedimentation cannot be said to exist. Further, they have shown that beef serum albumin or human serum albumin prolonged the sedimentation time when dissolved in Locke's solution or added to plasma.

Such controversial statements are found in the literature concerning the effects of the different protein fractions on sedimentation rate. We have briefly attempted to show some of the fundamental factors that influence sedimentation rate of erythrocytes. The method used in determining the sedimentation velocity is as follows : Whole oxalated blood was used.