Alterations in binding capacity or quantity of TBG may alter the free thyroid hormone level in blood. T3 uptake INCREASE: therapy with anticoagulants, salicylates, androgenic hormone, kidney disease, early infancy 1-9 weeks, metastatic malignancy, patients with abnormal serum protein patterns (e.g., nephrosis, hepatitis, cirrhosis), prednisone, butrazolidin, phenytoin, penicillin (large doses), polycythemia vera, supraventricular tachycardia (atrial arrhythmia), severe pulmonary insufficiency with CO2 retention, T3 uptake DECREASE: pregnancy, oral contraceptives, with administration of estrogen, Enovid, Premarin or Norlutin.