TSI (Thyroid Stimulating Immunoglobulin)

Preferred Specimen(s) 1 mL serum (red-top) tube

Transport Container Plastic screw-cap vial

Transport Temperature Refrigerated (cold packs)

Reject Criteria

  • Gross hemolysis
  • Hyperlipemia
  • Collected in a sodium heparin (green-top) tube

Methodology In vitro Bioassay/Luminescence

Clinical Significance Graves Disease is a classic form of hyperthyroid disease, affecting approximately 0.4% of the population in the United States. It is caused by IgG immunoglobulins, collectively known as thyroid stimulating immunoglobulins (TSI). Patients who are candidates for anti-thyroid drug therapy may not respond to this treatment when TSI levels are markedly elevated. The determination of TSI can also assist in predicting hyperthyroidism in neonates due to placental transmission of the immunoglobulins from a mother with hyperthyroidism.