· T3 Uptake – T3 uptake is used with measurement of thyroxine (T4) to calculate the free T4. This is a useful measurement in assessing thyroid diseases. Elevations are associated with hyperthyroidism or thyroid hormone resistance whereas low concentrations are associated with hypothyroidism.
· T4 (Thyroxine) – is the major secretory hormone of the thyroid. Only .03% of T4 is unbound and free for exchange with tissues. Thyroid function maybe be assessed with thyroid stimulating hormone (TSH) and free T4 measured.
· FTI (Free Thyroxine Index) – The FTI can be used as the most accurate measure of free T4 in the body. Results are independent of the concentration of the T4-binding proteins, the presence of molecular variants of these proteins or circulating auto-antibodies. Free T4 is useful in distinguishing euthryroidism from thyroid disease.
· TSH (Thyroid Stimulating Hormone) – TSH is the recommended test to identify hypothyroidism and hyperthyroidism. TSH is also useful to monitor thyroid hormone replacement therapy. Abnormal TSH levels should be followed by a free T4 test, since free T4 is more specific than TSH and serves to confirm thyroid dysfunction. A high TSH result will mean an underactive thyroid gland that is not responding adequately to the stimulation of TSH due to either an acute or chronic thyroid dysfunction. A low TSH result can indicate an overactive thyroid gland (hyperthyroidism) or excessive amounts of thyroid hormone medication. This could also indicate damage to the pituitary gland that prevents it from producing adequate amounts of TSH.
Cortisol
· Cortisol Salivary – The cortisol salivary test is a helpful diagnostic tool for the evaluation of the adrenal function, particularly hypercortisolism. Cortisol has a range of roles in the body. It helps break down protein, glucose, and lipids, maintain blood pressure, and regulate the immune system. The hormone is secreted in a daily pattern, rising in the early morning, peaking around 8 am and declining in the evening. Inadequate amounts of cortisol can cause nonspecific symptoms such as weight loss, muscle weakness, fatigue, low blood pressure and abdominal pain. Too much cortisol can cause increased blood pressure, high blood sugar, obesity, fragile skin, purple streaks on the abdomen, muscle weakness and osteoporosis.
