Correlations between radioiodine uptake and blood viscosity factors in hypothyroid and hyperthyroid states.

A study of blood viscosity factors was undertaken in six hypothyroid and eleven thyrotoxic patients (females) whose thyroid function was defined by means of radioiodine uptake and protein bound (PB) 131I tests. Results indicate that: (i) significant differences exist between hypothyroid and hyperthyroid groups in correlations between radioiodine tests and blood viscosity factors (and fibrinogen levels); (ii) blood viscosity in thyrotoxic patients decreases as the degree of thyrotoxicity increases, while an opposite phenomenon is observed in hypothyroid patients, and (iii) degree of rigidity of the red cells is associated with the radioiodine uptake and PB 131I tests, the correlations being significant and negative.