What does high free thyroxine index mean?
High levels of any of these tests (total T4, free T4, or free T4 index) may indicate an overactive thyroid, also known as hyperthyroidism. Low levels of any of these tests (total T4, free T4, or free T4 index) may indicate an underactive thyroid, also known as hypothyroidism.
Is free thyroxine index same as free T4?
Free thyroxine (T4) can be measured directly (FT4) or calculated as the free thyroxine index (FTI). The FTI tells how much free T4 is present compared to bound T4. The FTI can help tell if abnormal amounts of T4 are present because of abnormal amounts of thyroxine-binding globulin.
What is the optimal level for free T4?
Free T4, which tests for the amount of T4 that is available in the body, should range between 0.8 to 1.8 nanograms per deciliter (ng/dL).
Is a high free T4 bad?
In an adult, the typical range for free T4 is between . 8 and 1.8 nanograms per deciliter. 10 An abnormally high free T4 level may indicate hyperthyroidism, thyroiditis, or goiter. It may also lead to additional tests for Graves’ disease.
What is a normal free thyroxine level?
In adults, normal levels of total T4 range from 5–12 micrograms per deciliter (mcg/dl) of blood. Normal levels of free T4 range from 0.8–1.8 nanograms per deciliter (ng/dl) of blood.
Which is better free T4 or total T4?
Free T4 travels into body tissues that use T4. Bound T4 attaches to proteins that prevent it from entering these tissues. More than 99% of T4 is bound. Because T4 is converted into another thyroid hormone called T3 (triiodothyronine), free T4 is the more important hormone to measure.
What should your thyroxine level be?
What are Perfect thyroid Levels?
The normal range of TSH levels in adults is between 0.4 to 4.0 mIU/L (milli-international units per liter). Some research suggests that this range should actually be more like 0.45 to 2.5 mIU/L. The TSH range may also vary slightly based on the testing facility where your blood is being analyzed.
What is the normal range for free T4 and TSH?
Total T4 levels should be approximately 4.5 to 12.5. A low T4 level with High TSH indicates hypothyroidism. Free T4 normal range is approximately 0.7 to 2.0. If the value is low, it indicates f hypothyroidism.
Is your free T4 really in the normal range?
Typical results in adults for the free T4 test generally range from 0.9 to 2.4 nanograms per deciliter (ng/dL). Like total T4 in adults, free T4 also varies in children according to age.
What causes low free T4?
The following medical conditions are some of the possible causes of Low basal free T4. There are likely to be other possible causes, so ask your doctor about your symptoms. Congenital. Pituitary tumour. Craniopharyngioma. Post cranial irradiation. Pituitary irradiation.
What can cause low T4 with normal TSH?
For doctors to diagnose and treat conditions related to an overactive thyroid, they also check levels of T3 and T4 in your blood. The causes of low TSH can be Graves’ disease, nodules that stimulate the thyroid, or inflammation.