Thyroid: what an abnormal result means

TSH is not a thyroid hormone. It is a pituitary hormone that drives the thyroid to work, and that is exactly why it is measured first: it responds most sensitively to changes. A raised TSH means the gland is underactive, and then tiredness, feeling cold, constipation, dry skin and weight gain are to the fore. A low TSH means it is overactive, which shows as a pounding heart, trembling hands, sweating, restlessness and weight loss despite an unchanged appetite. How much hormone the gland actually produces is shown by the thyroid hormones, which are measured alongside TSH.

A borderline deviation is not the same as illness. A mildly raised TSH with a normal free T4 is called subclinical hypothyroidism and often does not need immediate treatment, but a repeat test after a few weeks or months. The value fluctuates with the daily rhythm, during recovery from illness and with some medicines. It is also affected by dietary supplements, especially biotin preparations, which can distort the lab measurement even though they have nothing to do with the thyroid itself.

Thyroid nodules are common and most of them are not cancerous. Ultrasound assesses them by size and appearance, and on that basis it is decided whether monitoring is enough or whether a fine-needle aspiration for cytology is needed. Aspiration is not an operation and does not require a hospital stay, but it is the only test that reliably tells what kind of cells a nodule contains.

At the thyroid clinic, the examination begins with a conversation about your symptoms, changes in body weight, heart rate and thyroid disease in the family. This is followed by an examination of the neck, in which the doctor feels the gland and lymph nodes. Then the results and the ultrasound image are put together: the lab tells how the gland works, and the neck ultrasound how it is built. Only both together give an answer about what comes next. We also treat autoimmune diseases, the most common of which are Hashimoto’s thyroiditis and Graves’ disease, and adjust doses for people already taking replacement treatment.

For the assessment, comparison with older results is often more important than a single measurement, so bring them with you, even if they are several years old. Also bring a list of medicines and dietary supplements, especially those containing biotin, iodine or selenium. On the morning of the blood test, take your thyroid replacement medicine only after the blood has been drawn, and mention this at the test, as the timing affects the measured values.

A few signs deserve a quicker examination: a lump in the neck that is growing quickly, hoarseness that does not go away, difficulty swallowing or a feeling of pressure that is getting worse, and a fast, irregular heartbeat together with marked weight loss. These are not signs worth watching for months.

The thyroid clinic is self-pay, so you do not need a referral and can book yourself. Booking is managed by the provider that runs the clinic. You receive a report with recommendations after the examination; further monitoring often takes place with your personal doctor, and a follow-up visit to the thyroid specialist is agreed depending on the results.