What is the diameter of a fibrin fiber?

Altered fibrin fiber structure is linked to pathologic states, including coronary heart disease, ischemic stroke, and atherosclerosis. However, several different techniques are commonly utilized for studying fibrin structures, and comparison of results obtained using different techniques can be challenging due to lack of standardization. This study provides a path toward standardization by comparing fibrin fiber diameters for a range of physiologic fibrinogen and thrombin concentrations using multiple different complementary experimental methods. We determined fiber diameter using scanning electron microscopy (SEM), superresolution (stochastic optical reconstruction microscopy) fluorescence microscopy, and 4 commonly utilized turbidimetric approaches to determine the congruence between the results and the conditions under which each should be used. We found that diameter values obtained using SEM and superresolution imaging agree within 10% for nearly all conditions tested. We also found that when a wavelength range of 500 to 800 nm was used for measurements and accounting for the wavelength dependence of the refractive index and specific refractive index increment, diameters obtained using the corrected Yeromonahos turbidimetric approach agree with SEM within 20% for most conditions. We performed a systematic, multitechnique survey assessing fibrin fiber diameters under a range of biochemical conditions. The similarity in the diameter values obtained using SEM and superresolution imaging suggests that drying and fixation during SEM sample preparation do not dramatically alter fiber cross-sections. Congruence, under certain conditions, between diameter values obtained using SEM, superresolution fluorescence imaging, and turbidimetry demonstrates the feasibility of a fibrin diameter standardization project. •Comparison of fibrin fiber diameter between studies is challenging due to lack of standardization.•Diameters were determined using multiple techniques for a range of physiologic concentrations.•Diameters determined using superresolution and scanning electron microscopy usually agree within 10%.•Turbidimetry, under limited conditions, provides diameters within 20% of those determined using scanning electron microscopy.