This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
TSH is normal in: September 2006 
Select and explain. 
A. Hypehyroid, B. Euthyroid, C. Hypothyroid, D. Graves
B: Euthyroid
Answer: B: Euthyroid 
Explanation: Ans. B: EuthyroidIn hypehyroidism:Total plasma T3, T4, 3 is highFree plasma T3, T4, 3 is highPlasma TSH is lowIn hypothyroidism:Total plasma T3, T4, 3 is lowFree plasma T3, T4, 3 is lowPlasma TSH is highGraves disease is most common cause of hypehyroidism.