Test Details: TSH helps to evaluate thyroid gland function and to help diagnose thyroid disorders. Thyroid stimulating hormone secreted by pituitary gland stimulates thyroid gland to release T3 and T4. TSH release in turn is stimulated by Thyrotropin releasing hormone secreted by hypothalamus. TSH test is useful in diagnosis and monitoring of hypothyroidism, hyperthyroidism, new born screening and also as an adjunct to infertility.