Triiodothyronine (T3) Free Blood Test, Dialysis and LC/MS-MS (Endocrine Sciences)

What is a thyroid?

The thyroid is a gland in the neck, above the collarbone, shaped like a butterfly. The thyroid is one of the endocrine glands, which produce hormones. These thyroid hormones help regulate the rate of many activities in the body, such as how fast calories are burned and how fast the heart beats. 

What is the purpose of this test?

Order this Triiodothyronine (T3) Free Blood Test, Dialysis, and LC/MS-MS to measure the amount of Free T3 in a blood sample to help assess thyroid hormone function and screen for thyroid disorders. Triiodothyronine, known as T3, is a vital thyroid hormone that controls metabolism and ensures that the body can complete essential functions appropriately. Although most T3 in the blood is bound to proteins, some are unbound or free. The free T3 test measures the active form of T3 that is unbound. Therefore, a healthcare provider may order a Free T3 blood test to evaluate thyroid function if a thyroid disorder (hyperthyroidism or hypothyroidism) is suspected. In addition, the free T3 test may also be used to evaluate pituitary gland problems, assess the severity and type of thyroid disease, and monitor treatment for a thyroid condition.

When should I order the Triiodothyronine (T3) Free Blood Test, Dialysis, and LC/MS-MS?

Individuals may order this panel if they suspect thyroid problems. Common signs or symptoms associated with thyroid malfunction or disorders include:

• Fatigue
• Weight loss or gain
• Chills
• Painful joints and muscles
• Dry skin
• Thin/dry hair
• Irregular heart rate
• Constipation
• Depression and anxiety
• Mood swings
• Irregular menstrual periods
• Infertility
• Insomnia
• Frequent bowel movements