Dynamic Viscosity of Blood Serum Determined Using Proton Magnetic Relaxation

An experimental procedure, based on proton magnetic relaxation, is presented to determine the absolute dynamic viscosity in blood serum (η_S). The blood serum samples were obtained voluntary from whole blood of healthy individuals and patients, and processed by classical methods (centrifugation and decanting). The Carr–Purcell–Meiboom–Gill pulse sequence was employed to determine the transverse proton magnetic relaxation time (T₂) in a Tecmag Magnetic Resonance console coupled to a magnet of 0.095 T and the temperature of measurement was 293 K. A theoretical linear behavior of the transverse proton magnetic relaxation rate (1/T₂) as a function of η_S was obtained after the consideration of blood serum as an extremely diluted solution of albumin and globulins, and assuming a fast exchange of water molecules between the bound phase and the solvent. A value of η_S = 1.29 ± 0.07 mPa s was obtained in samples belonging to 20 voluntary healthy individuals, which statistically match with the value obtained using the Ostwald viscometer for the same samples (η_S = 1.32 ± 0.04 mPa s, P = 0.104319 > 0.05, α = 0.05). The potential medical utility of the presented proton magnetic resonance procedure was demonstrated in patients with Multiple Myeloma (24) and Sickle Cell Disease (34), in which η_S resulted increased with values of 1.40 ± 0.18 mPa s (P = 0.0137509 < 0.05, α = 0.05) and 1.36 ± 0.10 mPa s (P = 0.00809615 < 0.05, α = 0.05), respectively.