Thyroid Panel 2

This panel offers a fuller assessment of your thyroid health, combining the main thyroid hormones with two antibody tests that can reveal an autoimmune cause of thyroid problems. As well as showing how well your thyroid is currently working, it helps identify whether your immune system may be involved, which is the most common underlying cause of thyroid conditions. It builds on our core thyroid panel with the addition of thyroid antibodies.

Thyroid hormones

• TSH (thyroid-stimulating hormone): produced by the pituitary gland to control the thyroid. It is the most sensitive first-line marker, rising when the thyroid is underactive and falling when it is overactive
• Free T4 (free thyroxine): the main hormone produced by the thyroid, giving a direct measure of thyroid output
• Free T3 (free triiodothyronine): the more active thyroid hormone, which can add useful information, particularly in assessing an overactive thyroid

Thyroid antibodies

These indicate whether your immune system is producing antibodies against your thyroid, pointing to an autoimmune thyroid condition:

• TPO antibodies (thyroid peroxidase antibodies): the main antibody marker, associated with autoimmune conditions such as Hashimoto's disease (a common cause of an underactive thyroid) and Graves' disease (a common cause of an overactive thyroid)
• Thyroglobulin antibodies (TG antibodies): a further antibody that can support the identification of autoimmune thyroid disease, sometimes present when TPO antibodies are not

What it can help assess

• Underactive thyroid (hypothyroidism): which can cause tiredness, weight gain, low mood, and feeling cold
• Overactive thyroid (hyperthyroidism): which can cause weight loss, anxiety, a fast heartbeat, and feeling hot
• Autoimmune thyroid disease: identifying whether an immune cause underlies a thyroid problem, which can help explain the condition and guide long-term monitoring

An important note on interpretation

Thyroid hormones and antibodies are best interpreted together, as the overall pattern reveals more than any single value. It is worth knowing that some people have thyroid antibodies without any current thyroid problem, which can indicate a higher chance of developing one in the future rather than a condition now. Levels can also be affected by illness, certain medications, and pregnancy. Any abnormal result should be discussed with your GP, who can interpret it in context and advise on any further testing or treatment.

Why it matters

Thyroid problems are common, and the most frequent causes are autoimmune. By checking your thyroid hormones alongside both main thyroid antibodies, this panel gives a fuller picture of your thyroid health, helping to detect a thyroid condition, identify an autoimmune cause, and understand your longer-term risk, so you and your doctor can plan appropriate monitoring and care.

• Thyroid-stimulating hormone (TSH)
• Free thyroxine (fT4)
• Free triiodothyronine (fT3)
• Thyroid peroxidase antibodies (TPO antibodies)
• Thyroglobulin antibodies (TG antibodies)

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.