Low platelet adhesiveness and other hemostatic abnormalities in hypothyroidism.

Fifteen patients with definite hypothyroidism and two with probable hypothyroidism had extensive hemostatic profiles done. In 12 of the 16 patients tested, the platelet adhesiveness (platelet retention in a glass bead column) was abnormal, and in 1 more it was borderline. In the six patients who were studied repeatedly, hemostatic abnormalities either markedly improved or disappeared after treatment with L-thyroxine. It is concluded that, in addition to the previously reported coagulation factor deficiencies (which we also observed in some of our patients), low platelet adhesiveness occurs frequently in patients with hypothyroidism.