TSH receptor antibody test

Your doctor may recommend the test if they believe that you have Grave’s disease. The symptoms of Grave’s disease are as follows:

• Bulging eyes
• Nervousness
• Symptoms in the eyes:
  • Irritation
  • Double vision
  • Trouble moving eyes
  • Light sensitivity
• Weight loss
• Irritability
• Extreme tiredness
• Low tolerance for heat
• Muscle weakness
• Trouble sleeping
• Irregular heartbeat
• Tremors in the hand
• Redness and swelling of shins
• Diarrhoea 
• Goitre (swollen thyroid)

The test is also ordered for people who show ambiguous symptoms of thyrotoxicosis or for whom the thyroid radioisotope scans are contraindicated, such as in pregnant or breastfeeding women.

Additionally this test aids in assessing the risk of relapse of Grave’s disease after treatment.

No special preparation is required. Women should tell their doctor if they are pregnant. Certain drugs may affect the results of this test. So, convey to your healthcare provider about all the medicines, vitamins and supplements that you are consuming.

Additionally, notify your doctor if you have undergone any imaging test recently as recent use of radioactive iodine - a solution injected in the body before some imaging tests - can alter the test results.

This test is conducted on a blood sample. The required amount of blood will be drawn from a vein in your arm. You may feel some pain when the needle is inserted. After the test, there may be slight bruising at the puncture site, however, the bruise will fade away soon. If you notice an infection at the blood withdrawal site, inform your doctor as soon as possible.

Normal results:

The test results are expressed either as percentage or TSI index. Usually, values below 130% or a TSI index below 1.3 is considered normal. Your doctor may follow different reference standards; therefore, speak to your doctor in case of doubts. 

You may have an autoimmune disease even if your test results are normal. If your healthcare provider suspects that you may develop the antibodies in future, they may order for a repeat test after some time.

Abnormal results:

If your test results show the presence of TSI in blood, it is an indication of Grave’s disease. Also, the test results may be elevated in the following conditions:

• Neonatal thyrotoxicosis (a disorder of newborns, in which, baby has raised levels of thyroid hormone due to high levels of thyroid hormones of the mother)
• Hashitoxicosis (a condition characterized by increased thyroid activity that is caused due to inflammation related to Hashimoto’s thyroiditis)
• Hyperthyroidism
• Autoimmune thyroiditis

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.