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Test Code TSIM Thyroid-Stimulating Immunoglobulin, Serum

Additional Codes

Mayo TSI
Epic ID LAB2755

 

Specimen Type

Serum


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


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

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.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Frozen (preferred) 60 days
  Refrigerated  7 days
  Ambient  24 hours
UPH Waterloo Region Lab Test Catalog Note:

Transport frozen.

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Method Name

Recombinant Bioassay

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).

Day(s) Performed

Monday through Friday

Report Available

2 to 6 days

Reference Values

≤1.3 TSI index

Reference values apply to all ages.

CPT Code Information

84445