Description
Test details
- TSH (thyroid stimulating hormone): the signal from the brain that tells the thyroid how much hormone to make. It is the most common first thyroid test.
- Free T4: the main hormone the thyroid makes. “Free” means the part not attached to proteins, which is the part the body can use.
- Free T3: the more active thyroid hormone. The body makes it mostly from T4.
- TPO antibodies (thyroid peroxidase antibodies): immune system markers that can be raised in autoimmune thyroid conditions such as Hashimoto’s thyroiditis.
- Thyroglobulin antibodies: another immune marker that can be raised in autoimmune thyroid conditions.
- Blood sample, collected in person at our Buffalo Grove or Lake Zurich location. For ages 18 and older. The person being tested must bring a matching photo ID.
How?
- Buy the test online, then visit either location for a short blood draw.
- A morning collection is generally preferred, since TSH is usually highest overnight and early morning.
How long?
- Results are typically ready in 2-3 days after the lab receives your sample. Some results take longer.
How to prepare?
- Fasting is generally not required for thyroid tests, though some labs ask for it. Follow the instructions given when you order and at your visit.
- Stop biotin and hair, skin and nail supplements at least 72 hours before your draw. Biotin can change thyroid test results.
- If you take thyroid medicine, ask your prescriber whether to take it before or after your draw. Do not stop or change a medicine without asking your prescriber.
- Tell the person drawing your blood about all medicines and supplements you take.
Do I need to see a doctor?
- A doctor’s visit is not required to buy this test.
- This test does not diagnose a condition. Review your results with your own healthcare provider.
Additional information about the panel
People order a thyroid panel when they have symptoms that can go along with thyroid changes, such as tiredness, weight change, feeling too cold or too hot, hair thinning, a fast or slow heartbeat, or changes in mood or periods. Many other conditions can cause the same symptoms, and this test may not explain them.
It is also used by people with a known thyroid condition, a family history of thyroid disease, or an autoimmune condition. Thyroid levels can change during and after pregnancy and around menopause.
Results are shown with reference ranges from the performing laboratory. A result is a snapshot of the time of your blood draw. A healthcare provider looks at results together with your symptoms and history.
If you only want a TSH check, see the Thyroid Function Test (TSH). Related tests include the Female Hormone Panel, the Anemia Panel and the Vitamin D Test.
What is included in a comprehensive thyroid panel?
This panel measures TSH, free T4, free T3, TPO antibodies and thyroglobulin antibodies in a blood sample.
Why test more than TSH?
TSH shows how hard the brain is signaling the thyroid. Free T4 and free T3 show the thyroid hormones themselves, and the antibody tests look for immune activity linked to autoimmune thyroid conditions.
Do I need to fast for a thyroid panel?
Fasting is generally not required, though some labs ask for it. Follow the instructions given when you order and at your visit.
Can biotin affect thyroid test results?
Yes. Biotin can change results. Stop biotin and hair, skin and nail supplements at least 72 hours before your draw, and ask your prescriber before changing any medicine.
What do raised thyroid antibodies mean?
Raised TPO or thyroglobulin antibodies can be seen in autoimmune thyroid conditions such as Hashimoto’s thyroiditis. They do not diagnose a condition by themselves, so review them with your healthcare provider.
Do I need a doctor’s order?
A doctor’s visit is not required to buy this test. Review your results with your own healthcare provider.
Safety and when to get care
- A very fast or irregular heartbeat, severe tremor, fever with confusion, or fainting needs emergency care.
- If you take thyroid medicine, keep taking it as directed. Your provider should adjust the dose.
- This test is not an emergency service. For severe or sudden symptoms, call 911 or go to the nearest emergency room instead of waiting for results.
Questions about this test
What does the Comprehensive Thyroid Panel include?
TSH, free T4, free T3, TPO antibodies (thyroid peroxidase) and thyroglobulin antibodies. It is the full workup for thyroid function and autoimmune thyroid disease.
Can this panel detect Hashimoto’s?
Yes. Elevated TPO antibodies, and often thyroglobulin antibodies, indicate Hashimoto’s thyroiditis, the most common cause of hypothyroidism. Antibodies can be positive years before TSH changes.
Why test free T3 in addition to TSH and free T4?
T3 is the active thyroid hormone. Some people have normal TSH and T4 but low T3 conversion, and T3 is the key marker in hyperthyroidism and Graves’ disease.
Do I need to fast for the Comprehensive Thyroid Panel?
No. Stop biotin supplements for 72 hours before the draw. If you take thyroid medication, draw before your morning dose.
What does it mean if my TSH is high or low?
High TSH with low free T4 is hypothyroidism. Low TSH with high free T4 or T3 is hyperthyroidism. High TSH with normal T4 is subclinical hypothyroidism, often monitored rather than treated. Positive antibodies point to an autoimmune cause.
How long do Comprehensive Thyroid Panel results take?
2 to 3 business days. Antibody tests take a day longer than TSH and T4.
