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Thyroid Stimulating Immunoglobulin

Item Value
Clinical Questions Does my patient have autoimmune thyroiditis?
Approval req'd? No
Available Stat? No
Test code TSI
Test group Thyroid tests
Performed by Quest
Sendout? Yes
Method Immunoassay
Container type Gold top, Red top
Amount to Collect 4 mL blood
Sample type Serum
Preferred volume 1 mL serum
Min. Volume 0.2 mL serum
UCSF Rejection Criteria Gross hemolysis, gross lipemia, grossly icteric samples
Processing notes Freeze at -20C. Order Quest # 30551
Ref Lab Rejection Criteria Gross hemolysis, gross lipemia, grossly icteric samples
Units % of baseline
Normal range Negative <140% of baseline (See Additional information)
Synonyms TSI; TSH receptor antibodies; Human Thyroid Stimulator (HTS); Long-Acting Thyroid Stimulator (LATS); Thyroid-Stimulating Antibody (TSAb)
Stability Refrigerated 3 weeks, frozen at -20C 2 months.
Turn around times Set up 5 days per week. Turnaround 3-6 days
Additional information A positive result is one in which the Specimen to Reference Ratio (%) (SSR%) is >140% of the Reference Control.

Thyroid stimulating immunoglobulins (TSI) can engage the TSH receptors resulting in hyperthyroidism in Graves' disease patients.
TSI levels can be useful in monitoring the clinical outcome of Graves' disease as well as assessing the potential for hyperthyroidism from maternal-fetal transfer.

NOTE: A serum TSH level greater than 350 µIU/mL can interfere with the TSI bioassay and potentially give false positive results.
CPT coding 84445-90
LOINC code 30567-2
Last Updated 6/21/2016 12:22:28
Entry Number 925
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