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Test Code TSI Thyroid-Stimulating Immunoglobulin, Serum

Test Down Notes

This test is temporarily unavailable. For additional details, see test update here.


Ordering Guidance


This test is used for second-order testing for autoimmune thyroid disease.

 

For suspected cases of autoimmune hypothyroidism, the first-order testing is TPO / Thyroperoxidase Antibodies, Serum.

 

For suspected cases of autoimmune thyroid disease, first-order testing includes TPO and THYRO / Thyrotropin Receptor Antibody, Serum.



Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Children's Mercy Hospital Note:

CMH COLLECTION: 2 mL in red gel vacutainer

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 60 days
  Refrigerated  7 days
  Ambient  24 hours

Useful For

Second-order testing for autoimmune thyroid disease, including:

-Differential diagnosis of etiology of thyrotoxicosis in patients with ambiguous clinical signs or contraindicated (eg, pregnant or breast-feeding) or indeterminate thyroid radioisotope scans

-Diagnosis of clinically suspected Graves disease (eg, extrathyroidal manifestations of Graves disease: endocrine exophthalmos, pretibial myxedema, thyroid acropachy) but normal thyroid function tests

-Determining the risk of neonatal thyrotoxicosis in a fetus of a pregnant female with active or past Graves disease

-Differential diagnosis of gestational thyrotoxicosis versus first-trimester manifestation or recurrence of Graves disease

-Assessing the risk of Graves disease relapse after antithyroid drug treatment

 

A combination of TSI / Thyroid-Stimulating Immunoglobulin, Serum and THYRO / Thyrotropin Receptor Antibody, Serum is useful as an adjunct in the diagnosis of unusual cases of hypothyroidism (eg, Hashitoxicosis).

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Day(s) Performed

Monday through Friday

Report Available

2 to 6 days

Reporting Name

Thyroid-Stimulating Immunoglob, S

Reference Values

≤1.3 TSI index

Reference values apply to all ages.

Method Name

Recombinant Bioassay

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

84445