Thyroid Stimulating Hormone (TSH) is a glycoprotein hormone secreted by the pituitary gland and regulates the synthesis/ release of T3 and T4 by thyroid gland. Increased serum TSH is an early and sensitive indicator of decreased thyroid reserve and overt primary hypothyroidism. Decrease TSH levels is an indicator of TSH-independent hyperthyroidism (Graves disease). BioVision’s human TSH kit is a solid phase sandwich ELISA Kit. The samples, and anti-TSH-HRP conjugate are added to the wells coated with monoclonal antibody to TSH beta subunit. TSH in the sample binds to anti-TSH MAb on the well and the anti-TSH detection antibody then binds to TSH. Unbound protein and HRP conjugate are washed off by wash buffer. Upon the addition of the substrate, the intensity of color is proportional to the concentration of TSH in the samples. A standard curve is prepared relating color intensity to the concentration of the TSH. The sensitivity of this ELISA test is 0.05μIU/ml.