Thromb Haemost 2020; 120(01): 044-054
DOI: 10.1055/s-0039-1698460
Coagulation and Fibrinolysis
Georg Thieme Verlag KG Stuttgart · New York

Interpretation and Validation of Maximum Absorbance Data Obtained from Turbidimetry Analysis of Plasma Clots

1  Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
2  Department of Physics, Wake Forest University, Winston-Salem, North Carolina, United States
1  Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
1  Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
› Author Affiliations
Funding This work was supported by the National Research Foundation (grant numbers 120070 and 105700 to M.P.) and the Medical Research Society (Self-Initiated Research Grant to M.P.) of South Africa, by the National Heart, Lung, and Blood Institute of the National Institutes of Health (U.S.A.) under Award Number R15HL148842, and by Wake Forest University Pilot grant DM0741. Opinions expressed and conclusions arrived at are solely the responsibility of the authors and do not necessarily represent the official views of the funders.
Further Information

Publication History

22 July 2019

23 August 2019

Publication Date:
21 November 2019 (online)


Turbidimetry is used to characterize fibrin clot properties. In purified systems, maximum absorbance (MA) directly relates to fibrin fiber cross-sectional area. However, in plasma samples there are discrepancies in the relationships between MA and fibrinogen concentration, fiber diameter, other clot properties, and cardiovascular disease outcomes, which complicate data interpretation. This study aims to advance understanding of MA of plasma clots through testing how well it relates to fundamental dependence on fibrinogen concentration and fiber diameter as predicted by light scattering theory, other clot properties and lifestyle, and biochemical variables. Plasma samples from 30 apparently healthy individuals with a fibrinogen concentration from 2.4 to 6.4 g/L were included. We performed turbidimetry, permeability, scanning electron microscopy, and rheometry on in vitro formed plasma clots. MA correlated more strongly with fibrinogen concentration (r = 0.65; p < 0.001) than with fiber diameter (r = 0.47; p = 0.01), which combined explained only 46% of the MA variance. Of additional variables measured, only low-density lipoprotein cholesterol correlated with MA (r = 0.46; p = 0.01) and clot lysis (r = 0.62; p < 0.0001) but not with fiber diameter or fibrinogen concentration. MA correlated with clot lysis time (r = 0.59; p = 0.001), storage modulus (r = 0.61; p = 0.001), and loss modulus (r = 0.59; p = 0.001), and negatively with clot permeability (r = –0.60; p = 0.001) also after adjustment for fibrinogen concentration and fiber diameter. Increased MA is indicative of a prothrombotic clot phenotype irrespective of fibrinogen concentration. MA is more indicative of overall clot density than of fiber diameter. Other plasma components can alter internal fiber density without altering fiber diameter and should be considered when interpreting MA of plasma samples.

Authors' Contributions

M.P. and Z.d.L. designed the research; Z.d.L. and C.N. performed the experiments and analyzed the data; M.P., M.G., and Z.d.L. critically evaluated the results and wrote the manuscript. All authors approved the final manuscript and figures.

Supplementary Material