TSH Receptor Antibodies (TRAb)

Graves' disease (overactive thyroid)

TSH receptor antibodies (TRAb) are antibodies that attach to the receptors on thyroid cells that normally respond to TSH. In Graves' disease, these antibodies switch the thyroid on and make it produce too much hormone. The test helps confirm Graves' disease as the cause of an overactive thyroid and is important in pregnancy for women with current or past Graves' disease.

• To find out whether an overactive thyroid is caused by Graves' disease or by another condition
• To look into thyroid-related eye symptoms, such as bulging, gritty or sore eyes
• In pregnancy for women with current or past Graves' disease, as the antibodies can cross the placenta
• To help the doctor judge how Graves' disease is responding to treatment

You can eat and drink normally; fasting is not necessary. Keep taking anti-thyroid medicines and other regular medicines exactly as prescribed unless your doctor tells you otherwise. If you take biotin supplements, tell your doctor, as they can affect some antibody tests.

Sample

Blood sample

How it works

A small blood sample is drawn from a vein in your arm by the collector during the home visit. It takes a few minutes, and if you are pregnant you can sit or lie in whichever position is most comfortable.

Report

Within 4 days of collection.

A positive result in someone with an overactive thyroid strongly supports Graves' disease. A negative result makes Graves' disease less likely but does not fully rule it out, and other causes such as thyroid inflammation or overactive nodules may be considered. In pregnancy, a high level tells the doctor that the baby's thyroid may need to be monitored. Your doctor will interpret the result together with your thyroid hormone levels and symptoms.

One test: TSH Receptor Antibodies (TRAb), from one blood sample.