ARUP's Laboratory Test Directory

Thyroid Stimulating Immunoglobulin : 0099430
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Additional Technical Information
  


Mnemonic: TSI

Ordering Recommendation: Not routinely ordered. Secondary testing for autoimmune thyroid disease.
Methodology: Quantitative Bioassay/Quantitative Chemiluminescent Immunoassay
Performed: Mon-Sat
Reported: 2-5 days
Specimen Required: Collect: Plain red or serum separator tube.

Specimen Preparation: Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.7 mL)

Storage/Transport Temperature: Frozen.

Unacceptable Conditions: Plasma.

Stability (collection to initiation of testing): After separation from cells: Ambient: 2 hours; Refrigerated: 6 days; Frozen: 3 months
Reference Interval:
Effective August 20, 2012
Negative 122% basal activity or less
Positive 123% basal activity or greater

Interpretive Data: Positive results (123 percent or greater) are consistent with Graves disease but do not always correlate with the presence and severity of hyperthyroidism. Antibodies to the Thyroid Stimulating Hormone Receptor (TSHR) may be stimulating, blocking, or neutral. Stimulating antibodies mimic the action of TSH and cause hyperthyroidism (Graves disease). This test determines the net effect of all TSHR antibody types present in the serum specimen.

See Compliance Statement B: www.aruplab.com/CS
Note: An elevated Thyroid Stimulating Hormone (TSH) value above 6 mU/L may produce a weakly positive Thyroid Stimulating Immunoglobulin (TSI) result (123 percent or greater).
CPT Code(s): 84445
Cross References: TSI (Thyroid Stimulating Immunoglobulin)