Thyroid Autoantibodies (AtAb)

Clinical definition of the Thyroid Antibodies (AtAb) test
The immune system protects the body from foreign invaders such as bacteria and viruses by destroying the invaders with substances called antibodies produced by blood cells known as lymphocyte. The autoantibodies develop when a person’s immune system mistakenly recognizes components of the thyroid as foreign (not-self) and leads to chronic inflammation of the thyroid (thyroiditis), tissue damage, causing changes in thyroid function so that it no longer produces enough thyroid hormone. In hypothyroidism or hyperthyroidism, lymphocytes make antibodies against the thyroid that either stimulate or damage the gland, resulting in Hashimoto’s thyroiditis and Graves’ disease. Thyroid antibodies destroy thyroid cells, cause thyroid inflammation or cause thyroid cells to produce excess thyroid hormone.

Why is the Thyroid Antibodies (AtAb) test done?
Thyroid antibodies attack the thyroid causing changes in thyroid function. Thyroid antibody tests are carried out to determine an autoimmune thyroid condition and measures the quantity of specific thyroid autoantibodies. It helps diagnose an autoimmune disease and separate it from the other forms of thyroiditis.  It also helps in investigating the cause of a goiter and/or performed as a follow-up when other thyroid test results (such as T3, T4 and/or TSH) show signs of thyroid dysfunction.

What are the common signs/symptoms when the Thyroid Antibodies (AtAb) test is done?
Symptoms of Hypothyroidism (An underactive thyroid)

  • Muscle and Joint Pains, Carpal Tunnel/Tendonitis Problems
  • Fatigue
  • Exhaustion
  • Feeling run down and sluggish
  • Difficulty concentrating
  • Brain fog (mental confusion)
  • Unexplained or excessive weight gain
  • Dry coarse and/ or itchy skin
  • Dry coarse and/ or thinning hair
  • Feeling cold especially in the extremities
  • Constipation
  • Muscle cramps
  • Heavier, more frequent and more painful periods
  • High cholesterol
  • Depression

Symptoms of Hyperthyroidism (An overactive thyroid)

  • Shorter, lighter or infrequent menstruation
  • Low cholesterol levels 
  • Unexplained weight changes 
  • Anxiety or panic attacks
  • Nervousness
  • Irritability
  • Increased perspiration
  • Dry scaly fragile and thinning of skin
  • Severe hair loss
  • High cholesterol
  • Unexplained weight changes
  • Loss of hair in the outer edge of the eyebrow

Who should do the Thyroid Antibodies (AtAb) test (Target population)?
Persons showing symptoms suggestive of hyperthyroidism and hypothyroidism.

What should I do before the Thyroid Antibodies (AtAb) test?

Specimen type

Specimen collection procedure

Preparatory instructions before the test *

Serum (Blood Sample)


Collection of blood from a vein, usually from the arm.

 No Fasting Required.

No other special preparations required.

*Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my Thyroid Antibodies (AtAb) test results?

Reference Range*



upto 34 Iu/ml


upto 115 Iu/ml

‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’

Diseases/conditions related to the Thyroid Antibodies (AtAb) test

  • Systemic Lupus Erythematosus
  • Rheumatoid Arthritis
  • Pernicious Anemia
  • Thyroid cancer
  • Hashimoto’s thyroiditis
  • Type 1 diabetes

Other tests related to the Thyroid Antibodies (AtAb) test

  • T3
  • T4
  • TSH
  • Thyroglobulin

Synonyms : Antithyroid antibodies, Thyroid microsomal antibody