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Doctor's Assessment Included

Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

Thyroid

TSI (Thyroid Stimulating Immunoglobulin)

TSI antibodies are linked to Graves' disease and thyroid overactivity. For adults over 60, thyroid conditions may sometimes present with subtle or atypical symptoms. Regular monitoring, as advised by your healthcare provider, can support early detection and appropriate management.

What It Measures

This test measures thyroid-stimulating immunoglobulin antibodies in your blood. These antibodies may bind to TSH receptors on the thyroid gland, potentially stimulating excess thyroid hormone production. TSI is considered a key diagnostic indicator that healthcare providers use when evaluating suspected Graves' disease.

Why It Matters

In older adults, Graves' disease may sometimes manifest differently, with symptoms like irregular heartbeat or unexplained weight changes that could be attributed to other conditions. TSI testing may help your healthcare provider make a more accurate diagnosis and develop an appropriate care plan.

When to Test

Healthcare providers may recommend TSI testing when hyperthyroidism is suspected, particularly if symptoms such as unexplained weight loss, rapid heartbeat, or eye changes are present. It may also be used to monitor Graves' disease treatment progress or during pregnancy when thyroid antibodies could affect the baby.

Symptoms

Low Levels

Low or undetectable TSI levels are generally considered normal and typically do not cause symptoms. The absence of these antibodies may suggest that Graves' disease is less likely as a cause of any thyroid-related symptoms you may be experiencing. Consult your healthcare provider for a comprehensive evaluation.

High Levels

Some people with elevated TSI may experience symptoms associated with hyperthyroidism, such as unexplained weight loss, increased heart rate, tremors, heat intolerance, anxiety, or eye protrusion. These symptoms may vary in severity. Your healthcare provider can recommend appropriate next steps based on your individual situation.

Lifestyle Tips

While lifestyle changes alone may not directly lower TSI levels, some people find that stress management techniques, adequate sleep, and a balanced diet may support overall thyroid health. Avoiding excessive iodine intake is sometimes recommended. Always follow your healthcare provider's guidance regarding treatment and lifestyle modifications.

Frequently Asked Questions

What is the difference between TSI and TSH?
TSH is a hormone produced by the pituitary gland that regulates thyroid function. TSI is an antibody produced by the immune system that may mimic TSH, potentially causing the thyroid to produce excess hormones. Your healthcare provider can explain how these markers relate to your health.
Can TSI levels change over time?
Yes, TSI levels may fluctuate depending on disease activity and treatment. Some people may see levels decrease with successful treatment of Graves' disease. Regular monitoring, as recommended by your healthcare provider, can help track these changes.
Is fasting required before a TSI test?
Fasting is generally not required for a TSI blood test. However, it is advisable to follow any specific preparation instructions provided by your healthcare provider or testing facility to ensure accurate results.