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Test Code
TSIG
Test Name
Thyroid-Stimulating Immunoglobulin (TSI)
CPT Codes
84445
Expected Turnaround Time
2 - 4 days
Clinical Utility

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.
Specimen and Container Info

Preferred Specimen Type: Serum 

Alternate Specimen Type: Plasma

 

Preferred Collection Container: Gold Top, Serum Separator or Red Top, Plain

Alternate Collection Container: Lavender Top (EDTA) 

 

Desired Specimen Volume: 1 mL
Collection Instructions
  1. Collect a gold top serum separator tube via venipuncture.
Processing and Submission Instructions
  1. Separate serum from cells as soon as possible or within 2 hours of collection.  
  2. Transfer 3 mL of serum to a clear aliquot tube (screw cap).
Patient Preparation

 Prepare sterile venipuncture site.
Transport Instructions

Transport to the laboratory refrigerated. 
Stability Requirements

Room Temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/Thaw Cycles

 Stable x3
Causes for Rejection
  • Gross lipemia
Methodology
IMMULITE 2000 TSI assay
Reference Intervals

See patient report.
Limitations

Heterophilic antibodies in human serum can react with the immunoglobulins included in the assay components causing interference with in vitro immunoassays. For diagnostic purposes, the results obtained from this assay should be used in combination with the clinical examination, patient medical history, and other findings.
Reference Lab
Labcorp Of America Holdings
Testing Schedule
Monday-Friday
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
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