Because there is insufficient T4, the body can compensate by converting T4 to T3 at a higher than usual rate, hence we see a T3 that is higher than T4 on a relative scale.
Free T4: Reflects the biologically active (free) form of T4. This T4 can be conver.
Whens the last time you went to the doctor and gave a blood sample that was then sent to a lab? Chances are that lab result came back normal. Too often, when interpreting lab values, the doctor looks for normal rather than optimal.
Both are in the normal range and therefore would be considered normal. In reality, however, simply looking at a short/obese man next to a tall/thin and a possibly undernourished man would suggest that the two are more than likely not in the same state of health.
The Thyroid Scale helps us compare thyroid lab values to each other and thus see their implications more clearly. It can be a line diagram or a table of lab values to visually depict how TSH, T4, and T3 relate to each other.
Normal is not the same as optimal, whether it relates to longevity of life, a body temperature or a lab test result. Thyroid levels are a critical component of determining the cause of low metabolic energy.
Normal rather than Optimal. The frequently used term of normal refers to a mathematical or statistical situation. Thus, a normal state of health probably means you have some medical problems. It may be normal to die at 76 yrs of age, but at 75 years old, you may decide that what you really want is.
T3 allows the body to turn up the energy when it needs to. RT3: Reverse T3 is made by the body to tone down energy. It is made by removing a different iodine from T4.
Nelson JC, Clark SJ, Borut DL, et al. Age related changes in serum free thyroxine during childhood and adolescence. J Pediatr. 1993;. Fisher DA. Physiological variations in thyroid hormones; physiological and pathophysiological considerations.
It is an approximation. Nonetheless, as a clinical tool, it seems to be more informative than the alternative which is to call a lab value low, normal, or high. After using it several times, you will probably wonder how anyone can use a term like normal to describe a relationship as complex as the one.
To do this with your lab values, there is a thyroid scale and some possible scenarios detailed down below. For now, lets do some simple exercises here to see how we can interpret some lab values.
Pituitary gland disease. Destruction of the thyroid gland by surgery or radiation.
Clin Chem. 1996;. Ridgway EC. Modern concepts of primary thyroid gland failure. Clin Chem. 1996;. Nicoloff JT, Spencer CA. The use and misuse of the sensitive thyrotropin assays. J Clin Endocrinol Metab.
This means that a value that falls outside the normal values listed here may still be normal for you or your lab. Results are usually available within a few days. Labs generally measure free T4 (FT4) levels, but also may measure total thyroxine (T4) and T3 uptake (T3U).
Thyroid lab values show are: TSH 5 (high FT4 0.7 (low FT3 280 (lower than optimal but relatively higher than T4) What does this mean: The pituitary gland is sensing insufficient thyroid energy and is therefore sending a strong signal to the (absent) thyroid gland telling it to make more T4.
Below you will find further explanation and greater detail to help you understand the logic behind these illustrations and how to interpret lab values. (return to top) Thyroid Function Tests Hormones (T4, T3, and RT3 once released into the bloodstream, exist either as protein bound or in a free form.
Protein acts as a sponge or reservoir to which hormones bind and then can be freed. Hormone in free form is then available to interact with a cells receptor site to produce its hormonal effect.
It represents the pituitary's need or desire for more thyroid hormone (T4 or T3). Thus a high TSH level is like the pituitary saying it has a high need for thyroid hormone or the body can tolerate more thyroid energy than it is getting and it is meant to generate more thyroid hormone production.
Note that high levels of estrogens (birth control pills, non-bio-identical hormone replacement, or pregnancy) or estrogen dominance can increase the amount of the protein that binds T4. This will produce misleading elevated Total T4 values which can look like hyperthyroidism when it is not.