TSI (Thyroid Stimulating Immunoglobulin)

Test Code
30551


CPT Codes
84445

Preferred Specimen
1 mL serum


Minimum Volume
0.2 mL


Transport Container
Plastic screw-cap vial


Transport Temperature
Frozen Serum


Specimen Stability
Room temperature: Unacceptable
Refrigerated: 21 days
Frozen: 60 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Grossly lipemic • Grossly icteric • Plasma


Methodology
In Vitro Bioassay

Setup Schedule
Set up: Mon-Sat; Report available: 3 days


Reference Range
<140 % Baseline


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.


Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.