Thyroid-Stimulating Immunoglobulin (TSI)
Here’s what it reflects — and what to do about it.
Longetic pulls together every lab and record you’ve had, follows how Thyroid-Stimulating Immunoglobulin (TSI) changes over time, and explains what’s shifting — so you walk into your next appointment prepared, with reminders for retests along the way.
What is Thyroid-Stimulating Immunoglobulin (TSI)?
A type of antibody that specifically stimulates the thyroid, driving it to make more hormone.
Thyroid-stimulating immunoglobulin is an antibody that acts like thyroid-stimulating hormone and pushes the thyroid to make extra hormone. Higher levels can be associated with Graves disease and its overactive thyroid, and the test may also help evaluate thyroid eye disease or thyroid activity in pregnancy. TSI measures the stimulating action specifically, so it is related to but not the same as the broader TSH receptor antibody test.
What to know about Thyroid-Stimulating Immunoglobulin (TSI)
Understanding Thyroid-Stimulating Immunoglobulin (TSI) means knowing what it reflects, what tends to move it, and the signs that suggest it’s worth a closer look — so you can bring the right questions to your next appointment.
This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Medical Disclaimer.
References
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Peer-reviewed research
Original research articles and systematic reviews published in indexed journals and verified through PubMed or DOI.