Overview of Thyroid profile Total
What is Thyroid profile Total?
Preparation for Thyroid profile Total
- No special preparation required
Why Get Tested for Thyroid profile Total?
To diagnose any suspected thyroid disease (Hypothyroidism or Hyperthyroidism)
To monitor treatment in patients with thyroid diseases
To investigate the cause of infertility
Understand more about Thyroid profile Total
The thyroid gland (a small, butterfly-shaped gland located in front of the neck) secretes the following hormones:
Thyroid Stimulating Hormone (TSH), also called Thyrotropin is a hormone secreted into the blood by a gland present in the brain (Pituitary gland) and it tells your thyroid gland to make and release the thyroid hormones (T3 & T4) into your blood. The thyroid gland uses iodine from food to make the thyroid hormones.
The thyroid hormones are essential for growth and metabolism. If the thyroid gland produces very high amounts of these hormones (T3 and T4), you may experience symptoms of weight loss, rapid heartbeat, tremors, sweating, anxiety, increased sensitivity to heat etc. and this is known as Hyperthyroidism.
Also, the decreased production of thyroid hormones (T3 and T4) results in Hypothyroidism which may cause symptoms like weight gain, fatigue, slow heart rate, increased sensitivity to cold, depression, dry and thin hair etc.
There is a feedback system in the body to maintain stable amounts of the thyroid hormones (T3 and T4) in the blood. When thyroid hormone levels decrease, the pituitary gland is stimulated to release TSH. This high TSH in turn leads to the release of more thyroid hormones (T3 & T4) from the thyroid gland and vice-versa.
T3 and T4 circulate in the blood in two forms:
1) Bound form - It is bound to proteins present in blood and this prevents it from entering body tissues. The three main proteins in the blood that the thyroid hormones are bound to are albumin, transthyretin and Thyroxine-binding globulin (TBG), also called Thyroid hormone Binding Globulin (THBG).
2) Free form - It enters the body tissues where it's needed
The total T3 or total T4 includes both bound and free forms circulating in the blood. Hence, thyroid hormones can be measured as Free T3, Total T3, Free T4 and Total T4.
The total T3 and total T4 levels can be affected by the amount of protein available in the blood to bind to them.
What Results of Thyroid profile Total mean?
T3 (Triiodothyronine), Total Reference Range(s)
T4 (Thyroxine), Total
Thyroid Stimulating Hormone (TSH) Reference Range(s)
Premature Infants (28-36 Weeks)
1st Week of Life
Term Infants (>37 Weeks)
Serum or Cord Blood
5 Days-4 Weeks
- Low T4 and T3 along with high TSH level indicates hypothyroidism. The most common cause of hypothyroidism is Hashimoto thyroiditis
- High T4 and T3 along with low TSH indicate hyperthyroidism. The most common cause of hyperthyroidism is Grave’s disease
- Normal thyroxine (T4) and T3 along with high TSH usually indicates mild or subclinical hypothyroidism
- Normal T3 and T4 along with low TSH indicates mild or subclinical hyperthyroidism
Table 1. Interpretation of the Thyroid Profile Test results
Mild (subclinical) hypothyroidism
Low or normal
Mild (subclinical) hyperthyroidism
Elevated or normal
High or normal
Low or normal
Low or normal
Nonthyroidal illness; hypothyroidism due to the disease involving the pituitary gland
Thyroid hormone resistance (Impaired sensitivity to thyroid hormone)
Note: TSH levels show circadian variation (fluctuates during the 24-hour cycle), reaching peak levels between 2 - 4 am and are at a low between 6-10 pm.
Reference Range(s) may vary from lab to lab.
Patient Concerns about Thyroid profile Total
Frequently Asked Questions about Thyroid profile Total
Tests Included in Thyroid profile Total(3 tests)
- Thyroid Stimulating Hormone
- Thyroxine - Total