Test Directory

Thyroid-Stimulating Immunoglobulin, Serum

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Updated Test Information:

Test Description
Thyroid-Stimulating Immunoglobulin, Serum
Thyroid-Stimulating Immunoglob
Test ID
General Information
Useful for:
Second-order testing for autoimmune thyroid disease, including:
-Differential diagnosis of etiology of thyrotoxicosis in patients with ambiguous clinical signs or contraindicated (eg, pregnant or breast-feeding) or indeterminate thyroid radioisotope scans
-Diagnosis of clinically suspected Graves disease (eg, extrathyroidal manifestations of Graves disease: endocrine exophthalmos, pretibial myxedema, thyroid acropachy) but normal thyroid function tests
-Determining the risk of neonatal thyrotoxicosis in a fetus of a pregnant female with active or past Graves disease
-Differential diagnosis of gestational thyrotoxicosis versus first-trimester manifestation or recurrence of Graves disease
-Assessing the risk of Graves disease relapse after antithyroid drug treatment
A combination of TSI / Thyroid-Stimulating Immunoglobulin (TSI), Serum and THYRO / Thyrotropin Receptor Antibody, Serum is useful as an adjunct in the diagnosis of unusual cases of hypothyroidism (eg, Hashitoxicosis).
Specimen Type
Specimen Requirements
Frozen (preferred) 60 days
Refrigerated 7 days
Ambient 24 hours
Unacceptable Specimen Conditions
Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK
Recombinant Bioassay
Estimated TAT
2-6 days
Testing Schedule
CPT Code(s)
Minimum Sample Volume
0.1 mL
Reference Range
< or =1.3 TSI index
Reference values apply to all ages.
Performing Lab
LOINC Code(s)