Causes for Decreased Thyroxine-Binding Globulin

II. Decreased TBG

A. Certain medications

1. Androgens

2. Drugs that compete with T4 and T3 for binding sites on TBG or albumin (e.g., phenytoin, valproic acid, salicylate)

B. Severe nonthyroidal illness

C. Congenital Disease

D. Nephrotic syndrome or conditions leading to severe hypoalbuminemia

Previous slide

Next slide

Back to first slide

View graphic version