Affiliations: Faculty of Science, Centre for Biomedical Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia | Faculty of Mathematical and Computer Sciences, Centre for Biomedical Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia
Note: [] Address correspondence to: Associate Professor Loraine Holley, Department of Health Science, Faculty of Science, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia. Fax: +61 2 9514 2186; E‐mail: Loraine. Holley@ uts.edu.au.
Abstract: This study investigates the influence of haematocrit, fibrinogen concentration and fibrinogen availability (amount of fibrinogen per red blood cell) on erythrocyte sedimentation. The Westergren technique was applied to blood samples from 36 subjects and to their blood manipulated to haematocrits of 10, 20, 30 and 40%. Readings were taken every 10 minutes for 300 minutes. Previous studies indicate that erythrocyte sedimentation occurs in three phases. In this study, we show that haematocrit has little influence on either the rate of fall of particles in the first phase (m_{1}) or the duration of the first phase. This is also true for fibrinogen availability and for fibrinogen concentration at low haematocrits. At high haematocrits m_{1} increases with fibrinogen concentration. The rate of fall of rouleaux during phase 2 (m_{2}) and ESR_{60} both decrease exponentially with haematocrit and increase linearly with fibrinogen concentration. While m_{2} is more closely correlated to fibrinogen availability than to fibrinogen concentration or to haematocrit, this is not the case for ESR_{60}. Thus haematocrit, fibrinogen concentration and fibrinogen availability are more important to the velocity of sedimentation in the second phase than to the sedimenting velocity during phase 1 or to the duration of phase 1.
