Alpha Medical Lab

TSI (Thyroid Stimulating Immunoglobulin)

Ordered Test Code:

TSI

Lab Test Component	Requirement
Test Name	TSI (Thyroid Stimulating Immunoglobulin)
Alpha’s Order Test Code	TSI
Specimen Collection Tube	SST/1mL
Collection Tube Handling
Minimum Volume	0.2mL
Transport Temperture	Refrigerated
Stability	Refrigerated: 21 days; Frozen: 60 days
Collection Instructions	1mL serum

Clinical Significance

Graves’ disease is a classic form of hyperthyroid disease, affecting approximately 0.4% of the population of the United States. It is caused by IgG immunoglobulins, collectively known as thyroid stimulating immunoglobulins (TSI). Patients who are candidates for antithyroid 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.