If you need to know which are the T4 reference ranges or you require more information about the role of T4 in the blood, you can visit normal T4 level in the blood
Values of T4 (Thyroxine) below the normal range may be a sign of suffering from hypothyroidism, a disorder where the thyroid hormone fails to produce enough thyroid hormones.
T4 values should be studied along with the values of T3 hormone (Triiodothyronine) and TSH hormone (thyroid-stimulating hormone) for a better diagnosis.
There are two types of hypothyroidism that can be discerned by studying the TSH:
T4 blood values are usually given in µg/ml but sometimes you can see these values in nmol/l following the International System of Units (SI). In case your values are in nmol/l you can convert them using this tool:
Hypothyroxinemia or low T4 blood levels mean:
Your total T4 blood level is very low and it may be a sign of hypothyroidism.
If the TSH (thyroid-stimulating hormone) value is above the normal range is a sign of primary hypothyroidism. If the TSH value is below the normal range is a sign of secondary hypothyroidism.
A free T4 blood test may be asked because it can give more detailed information about the disorder than the total T4.
If your T4 level in the blood is low, you may suffer from fatigue or weight gain. You should visit your doctor or an endocrinologist to prescribe you a proper treatment.
In case of a low T4 level in a newborn, it may be a sign of congenital hypothyroidism.
Some particular health situation or drugs may reduce your T4 level in the blood:
The following diseases can explain a total T3 level in the blood lower than normal:
If your T4 (Thyroxine) level in the blood is lower than normal the following tips can help you:
You can visit our pages about:
The following values are considered to be above the normal range:
IMPORTANT: These levels are expressed in µg/dl. They are an example of a healthy man of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.
T4 | |||||||
|---|---|---|---|---|---|---|---|
| Marked hypothyroxinemia | |||||||
| 3.9 µg/dl | 3.8 µg/dl | 3.7 µg/dl | 3.6 µg/dl | 3.5 µg/dl | 3.4 µg/dl | 3.3 µg/dl | 3.2 µg/dl |
| 3.1 µg/dl | 3 µg/dl | 2.9 µg/dl | 2.8 µg/dl | 2.7 µg/dl | 2.6 µg/dl | 2.5 µg/dl | 2.4 µg/dl |
| 2.3 µg/dl | 2.2 µg/dl | 2.1 µg/dl | 2 µg/dl | 1.9 µg/dl | 1.8 µg/dl | 1.7 µg/dl | 1.6 µg/dl |
| 1.5 µg/dl | 1.4 µg/dl | 1.3 µg/dl | 1.2 µg/dl | 1.1 µg/dl | 1 µg/dl | ||
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