The detection of hormones at certain levels aids in diagnosing a number of conditions including pregnancy and thyroid disorders. In healthy patients, hCG in urine provides an early indication of pregnancy. Thyroid hormones, including TSH, T3 and T4, exert powerful and essential regulatory influences on growth, differentiation and cellular metabolism. Together, these three markers are important factors in the diagnosis of thyroid diseases, monitoring both patients under treatment for hyperthroidism and patients who have discontinued anti-thyroid drug therapy. During pregnancy, TORCH infections can be spread from a woman to her developing fetus and can cause severe damage to the fetus and congenital birth defects. The immune status and diagnosis of TORCH infections are typically made by serological testing to help determine the risk for transmission.