The Complete Thyroid Profile combines the four most clinically useful thyroid function tests, giving a thorough assessment of a patient’s thyroid function.
Thyroid disease or dysfunction can explain a wide variety of symptoms, yet it is notoriously under-diagnosed. Population studies such as the Colorado Thyroid Disease Prevalence Study demonstrate that up to 10% of Americans may have thyroid dysfunction, defined as abnormal levels of thyroid-stimulating hormone (TSH).
Overt hypothyroidism, with its characteristically high TSH and low circulating thyroxine (T4) levels, or hyperthyroidism, with low TSH and high T4 levels (most commonly manifested as Graves’ Disease), are relatively easy to recognize clinically. But an elevated TSH associated with normal thyroid hormone levels, defined as “subclinical” hypothyroidism, is thought to be present in 4-10% of the general population and in up to 20% of women over 60 years old, while a low TSH and normal thyroid hormone levels, or subclinical hyperthyroidism, occurs in about 2% of the population and is most common in women, blacks, and the elderly.
Thyroid hormones are primarily involved in directing the metabolic activity of cells, and a properly regulated thyroid is therefore essential to a wide array of biochemical processes in the body. Subclinical hypo and hyperthyroidism can therefore result in symptoms even when hormone levels appear to be normal, because the abnormal TSH indicates that there is still a disorder in thyroid regulation, and because thyroid hormone activity can be affected by interactions with other hormone systems, particularly estrogens and cortisol, and by some nutritional deficiencies. Management of thyroid dysfunction requires an understanding of these interactions and careful monitoring of treatment with regular thyroid function tests.
The presence of thyroid peroxidase (TPO) antibodies has been found to help diagnose thyroid disease in patients with abnormal TSH and/or mild thyroid symptoms, and is used to indicate the presence of autoimmune thyroiditis (Hashimoto’s disease, the most common cause of overt hypothyroidism), since 95% of such patients are positive for TPO antibodies.