Test Overview
Test Methodology

Chemiluminescent Immunoassay

Test Usage

Diagnosis of hyperthyroidism; diagnosis of patients with normal routine thyroid tests but in whom progessive exophthalemia and/or Grave's disease is still suspected.

Reference Range *

<0.55 IU/L
Thyroid Stimulating Immunoglobulin is measured by the Siemens Immulite 2000 Chemiluminescent Immunoassay method. The cutoff value of 0.55 IU/L was determined from a ROC curve analysis and has consistently shown a sensitivity of >98% and specificity of >99% for the diagnosis of Graves’ Disease.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Monday, Thursday
Analytic Time

2 - 7 days

Soft Order Code
TSI
MiChart Code
Thyroid Stimulating Immunoglobulin
Synonyms
  • LATS
  • LATS (Long Acting Thyroid Stimulator)
  • Long Acting Thyroid Stimulator (LATS)
  • TSI
  • TSIS
  • THYROID STIMULATION IG
Laboratory
Chemical Pathology
Section
Special Chemistry
Specimen Requirements
Collection Instructions

Collect blood in an SST tube. Centrifuge, aliquot serum into plastic vial and refrigerate up to 7 days or freeze for longer storage.

Alternate Specimen
Red Top (serum); lithium heparin and EDTA (plasma)
Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.3 mL serum
Billing
CPT Code
84445
Fee Code
KA028
LOINC
30567-2
Resources