What i being tested?
The Free T4 test is a blood test that measures the levels of the hormone thyroxine in the blood. It is usually performed as an additional test when TSH levels exceed the age and gender-specific reference range in patients aged 1 year or older. This test can help diagnose thyroid disorders such as hypothyroidism or hyperthyroidism. No special preparation is required for this test.
Reference Range
For the TSH with Reflex to Free T4 medical test, reference ranges vary depending on the age and condition of the individual. Premature infants (28-36 weeks) have a reference range of 0.20-27.90 mIU/L during the first week of life, while term infants (>37 weeks) have a range of 1.00-39.00 mIU/L for serum or cord blood. For term infants, the range decreases with age: 3.20-34.60 mIU/L for 1-2 days, 0.70-15.40 mIU/L for 3-4 days, 1.70-9.10 mIU/L for 5 days-4 weeks, 0.80-8.20 mIU/L for 1-11 months, and 0.50-4.30 mIU/L for 1-19 years. Individuals 20 years or older have a range of 0.40-4.50 mIU/L. In pregnancy, the reference range also varies by trimester: 0.26-2.66 mIU/L for the first trimester, 0.55-2.73 mIU/L for the second trimester, and 0.43-2.91 mIU/L for the third trimester.
Test Description
Why should you get a TSH with reflex to free T4 blood test?
A TSH (thyroid-stimulating hormone) with reflex to free T4 blood test is a diagnostic tool used to evaluate the health of your thyroid gland. The thyroid gland is a small butterfly-shaped gland located in the neck that produces hormones that help regulate metabolism and other vital bodily functions. This test measures the levels of TSH and free T4 hormones in your blood and can detect if your thyroid gland is overactive (hyperthyroidism) or underactive (hypothyroidism).
There are several reasons why you should consider getting this blood test. Firstly, if you are experiencing symptoms such as fatigue, weight gain or loss, mood changes, hair loss, or irregular menstrual cycles, it could be an indication of thyroid dysfunction. Secondly, if you have a family history of thyroid disease or have undergone radiation therapy in the neck area, you are at a higher risk of developing thyroid problems. Lastly, if you have been diagnosed with a thyroid disorder, this test can help monitor your condition and determine if your current treatment plan is working effectively.
What happens if you don't get a TSH with reflex to free T4 blood test?
If you don't get this blood test, you may not be aware of underlying thyroid dysfunction that could lead to serious health complications. An untreated thyroid disorder can affect your heart, bones, and reproductive system, and can even lead to a life-threatening condition called myxedema coma. It is essential to diagnose and treat thyroid problems promptly to prevent complications.
What will you find out from this blood test?
This blood test measures the levels of TSH and free T4 hormones in your blood, which can provide valuable information about the health of your thyroid gland. The TSH hormone stimulates the thyroid gland to produce hormones, while free T4 is a hormone produced by the thyroid gland. High levels of TSH indicate an underactive thyroid gland (hypothyroidism), while low levels of TSH indicate an overactive thyroid gland (hyperthyroidism). Free T4 levels help confirm the diagnosis and determine the severity of the condition.
What can you do with this information?
If your blood test results show that you have an underactive or overactive thyroid gland, your doctor may recommend treatment options such as medication, radioactive iodine therapy, or surgery, depending on the severity of your condition. Regular monitoring of your thyroid function with blood tests can help your doctor adjust your treatment plan as necessary and prevent complications.