Thyroid-stimulating Immunoglobulin (TSI)
Also known as: Human Thyroid Stimulator (HTS), Long-acting Thyroid Stimulator (LATS)
Use
The measurement of thyroid stimulating autoantibodies, in conjunction with other clinical and laboratory findings, is used as an aid in the diagnosis of patients suspected of having Graves' disease.1
Special Instructions
For diagnostic purposes, the results obtained from this assay should be used in combination with the clinical examination, patient medical history, and other findings. Prepare a sterile venipuncture site. Serum or plasma must be separated from blood cells by centrifugation, ideally within two hours of collection. If using a red-top tube or plasma, transfer the separated serum or plasma to a plastic transport tube.
Limitations
Heterophilic antibodies in human serum can react with the immunoglobulins included in the assay components, causing interference with in vitro immunoassays. Commonly used Thyrotropin Receptor Autoantibody assays do not distinguish between TSI and Thyroid Blocking Immunoglobulins (TBI). In the validation for FDA submission, TSI values for patients with other thyroid or autoimmune diseases had an upper limit of 0.39 IU/L. Discrepancy may occur in patients undergoing treatment.
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 30567-2
- 30567-2
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube or green-top (heparin) tube
Collection Instructions
Serum or plasma must be separated from blood cells by centrifugation, ideally within two hours of collection. If red-top tube or plasma, transfer separated serum or plasma to a plastic transport tube.
Patient Preparation
Prepare sterile venipuncture site.
Causes for Rejection
Gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |