Thyroid Package

Stimulating Immunoglobulin (TSI), Serum

What is TSI?

TSI or Thyroid Stimulating Immunoglobulins, are antibodies that bind to the TSH receptor on the thyroid cells, causing the uncontrolled production of thyroid hormones. This autoimmune disorder is known as Graves’ disease (GD). TSI are IgG antibodies that can cross the placental barrier, causing neonatal thyrotoxicosis.

What is the TSI test?

TSI test is a Chemiluminescent immunoassay (CLIA) that detects and quantifies TSI IgG in the blood.

Approach to diagnosis of Hyperthyroidism



Approach to diagnosis of Hypothyroidism

Approach to diagnosis of Hypothyroidism



Panel of tests offered by Aspira

Thyroid Panel 1

  • Total T3
  • Total T4
  • TSH Ultrasensitive

Thyroid Panel 2

  • Free T3
  • Free T4
  • TSH Ultrasensitive

Individual tests

  • TSH
  • Antithyroid antibodies
  • Anti TPO
  • Anti Tg
  • Thyroid stimulating immunoglobulin
  • TSI & Thyroglobulin

Normal Range :

Thyroid Stimulating Hormone (TSH)

Adult / PediatricRange (μIU/ml)
Premature Infants0.8 - 5.2
Cord Blood1.0 - 17.4
1 - 3 days1.0 - 17.4
1 - 3 days1.0 - 17.4
4 days - 4 months1.7 - 9.1
5 months - 2 years0.8 - 8.2
2 years - 11 years0.64 - 6.27
12 years - 17 years0.51 - 4.94
Above 18 years0.55 - 4.78

Clinical utility of Thyroid Stimulating Immunoglobulin measurement includes

  • Determination of autoimmune etiology of thyroxicosis.
  • Monitoring Graves’ patient therapy.
  • Prediction of remission or relapse.
  • Confirmation of Graves’ opthalmopathy.
  • Prediction of hyperthyroidism in neonates.
ParameterFree T4 (ng/ml)Free T3 (pg/ml)Total T4 (μg/dl)Total T3 (ng/dl)
Euthyroid0.89 to 1.762.30 - 4.204.5 - 10.960 to 181
HypothyroidLess than 0.89less than 2.300.0 - 5.5less than 60
HyperthyroidGreater than 1.76greater than 4.2010.8 - 19.1greater than 181