What causes low free T4 and normal TSH?
Table of Contents
What causes low free T4 and normal TSH?
A low TSH and low FT4 or FTI indicates hypothyroidism due to a problem involving the pituitary gland. A low TSH with an elevated FT4 or FTI is found in individuals who have hyperthyroidism. T3 tests are often useful to diagnosis hyperthyroidism or to determine the severity of the hyperthyroidism.
Can you have normal TSH and low T4?
Subclinical hyperthyroidism is a condition in which you have low levels of thyroid stimulating hormone (TSH) but normal levels of T3 and T4. T4 (thyroxine) is a major hormone secreted by your thyroid gland.
Why would free T4 be low?
Abnormally low free T 4 levels may signal hypothyroidism. This means your thyroid is not making enough hormones. An underlying condition, such as Hashimoto disease, another autoimmune disorder, could be the cause of an underactive thyroid.
How is low free T4 treated?
Treatment for hypothyroidism To treat this condition, a person takes the synthetic hormone levothyroxine daily to increase levels of the natural thyroid hormone thyroxine. When a person first starts taking levothyroxine, they require blood tests every 6–8 weeks .
Why do my thyroid levels keep dropping?
For people with thyroid disease, certain things can cause fluctuations in thyroid hormone levels. These may include disease progression, medication changes, other herbs and supplements, and the change of seasons.
Why is free T4 more accurate?
A Free T4 measures what is not bound and able to enter and affect the body tissues. Tests measuring free T4 – either a free T4 (FT4) or free T4 index (FTI) – more accurately reflect how the thyroid gland is functioning when checked with a TSH.
Does Synthroid increase free T4?
If the patient then receives levothyroxine replacement for their thyroid the free T4 levels will rise, and TSH levels often fall to below normal.
What level of free T4 indicates hypothyroidism?
Low T4 is seen with hypothyroidism, whereas high T4 levels may indicate hyperthyroidism. Normal range for an adult: 5.0 – 11.0 ug/dL (micrograms per deciliter of blood).