Serum TSH Receptor Antibody

Specimen Required

3-5cc Clotted Blood or Serum

Fasting Required

Purpose of the Test

To help diagnose and monitor autoimmune thyroid diseases and to distinguish these from other forms of thyroiditis, and thyroid disease; to help guide treatment decisions

When this test is required

Thyroid Antibody Acronym Present in When ordered Thyroid peroxidase antibody/thyroid microsomal antibody TPOAb Autoimmune thyroid disease: Hashimoto’s thyroiditis (95%); primary myxoedema (90%); Graves’ disease (18%) When patient has symptoms or test results suggesting hypothyroidism; when a doctor is considering starting a patient on a drug therapy, such as lithium, amiodarone, interferon alpha, or interleukin-2, that has associated risks of developing hypothyroidism when TPOAb are present Thyroglobulin antibody TgAb Tested as part of monitoring of treatment for thyroid cancer. Also present in autoimmune thyroid disease. Not as reliable as TPOAb in testing for autoimmune thyroid disease. Thyroglobulin antibody together with thyroglobulin levels are used at regular intervals after thyroid cancer treatment. The presence of thyroglobulin antibodies may interfere with the test for thyroglobulin which is also tested as a tumour marker. Thyroid stimulating hormone receptor antibody TRAb Graves’ disease When patient has symptoms of hyperthyroidism; to monitor effectiveness of anti-thyroid therapy If a pregnant woman has a known autoimmune thyroid disease (such as Hashimoto’s thyroiditis or Graves’ disease) or has another autoimmune disorder and thyroid involvement is suspected, then one or more of the thyroid antibodies may be requested early in the pregnancy and then again near the end. These tests are used to help the doctor determine whether the baby may be at risk of thyroid dysfunction since thyroid antibodies can cross the placenta and cause hypothyroidism or hyperthyroidism in the foetus or newborn.Thyroid antibody testing may also be requested when a patient is being investigated for infertility.

What the Test Detects

These tests detect the presence and measure the quantity of specific thyroid autoantibodies in the blood. These autoantibodies develop when a person’s immune system mistakenly recognises components of the thyroid gland or thyroid proteins as foreign (non-self) and can lead to chronic inflammation of the thyroid (thyroiditis), tissue damage, and disruption of thyroid function. The thyroid is a small, butterfly-shaped gland…These tests detect the presence and measure the quantity of specific thyroid autoantibodies in the blood. These autoantibodies develop when a person’s immune system mistakenly recognises components of the thyroid gland or thyroid proteins as foreign (non-self) and can lead to chronic inflammation of the thyroid (thyroiditis), tissue damage, and disruption of thyroid function. The thyroid is a small, butterfly-shaped gland that lies flat against the windpipe in the throat. The primary hormones that it produces (thyroxine (T4) and triiodothyronine (T3)) are vital in helping to regulate the rate at which we use energy. The body has a feedback system that utilises thyroid stimulating hormone (TSH) to help turn thyroid hormone production on and off and maintain a stable amount of the thyroid hormones in the bloodstream. When thyroid antibodies interfere with this process, it can lead to chronic conditions and disorders associated with hypothyroidism (not enough thyroid hormones) or hyperthyroidism (excessive amounts of thyroid hormones). Hypothyroidism can cause symptoms such as weight gain, fatigue, goitre (enlarged thyroid gland), dry skin, hair loss, intolerance to cold, and constipation. Hyperthyroidism can cause symptoms such as sweating, rapid heart rate, anxiety, tremors, fatigue, difficulty sleeping, sudden weight loss, and protruding eyes.How is the sample collected for testing?A blood sample is obtained after inserting a needle with syringe into a vein in the arm.Is any test preparation needed to ensure the quality of the sample?No test preparation is needed. See MoreSee Less

Preparation for the Test

None

Sample Requirements

A blood sample taken from a vein in your arm

Additional Notes

There are a variety of different methods available for measuring thyroid antibodies, and different laboratories may use different methods, which may measure slightly different things. As a result of this, different laboratories may quote different reference ranges for resultsIf you are having serial testing done (for monitoring purposes), it is therefore important to have testing done by the same laboratory using the same method.

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