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Test Code Billings Clinic: 1921 Mayo: TGAB Thyroglobulin Antibody, Serum

Reporting Name

Thyroglobulin Antibody, S

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

As an adjunct in the diagnosis of autoimmune thyroid diseases: Hashimoto disease, postpartum thyroiditis, neonatal hypothyroidism, and Graves disease

Method Name

Immunoenzymatic Assay


Ordering Guidance


For the follow-up of patients with differentiated follicular cell-derived thyroid carcinomas, consider either HTG2 / Thyroglobulin, Tumor Marker, Serum or HTGR / Thyroglobulin, Tumor Marker Reflex, Serum.

 

The preferred method for confirming Graves disease in atypical cases or under special clinical circumstances is measurement of the pathogenic antithyrotropin receptor antibodies by binding assay or bioassay. Order either THYRO / Thyrotropin Receptor Antibody, Serum or TSI / Thyroid-Stimulating Immunoglobulin, Serum.



Specimen Required


Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube: Red top (gel tubes/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.6 mL serum

Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.


Specimen Type

Serum Red

Specimen Minimum Volume

Serum: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 7 days
  Frozen  30 days
  Ambient  7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus Reject

Reference Values

<4.0 IU/mL

Reference values apply to all ages.

Interpretation

Diagnosis of Autoimmune Thyroid Disease:

Measurements of antithyroperoxidase (anti-TPO) have higher sensitivity and equal specificity to antithyroglobulin (anti-Tg) measurements in the diagnosis of autoimmune thyroid disease. Anti-Tg levels should, therefore, only be measured if anti-TPO measurements are negative but clinical suspicion of autoimmune thyroid disease is high.

 

Detection of significant titers of anti-Tg or anti-TPO autoantibodies is supportive evidence for a diagnosis of Graves disease in patients with thyrotoxicosis. However, measurement of the pathogenic antithyrotropin receptor antibodies by binding assay (THYRO / Thyrotropin Receptor Antibody, Serum) or bioassay (TSI / Thyroid-Stimulating Immunoglobulin, Serum) is the preferred method of confirming Graves disease in atypical cases and under special clinical circumstances.

 

Positive thyroid autoantibody levels in patients with high-normal or slightly elevated serum thyrotropin levels predict the future development of more profound hypothyroidism.

 

Patients with postpartum thyroiditis with persistently elevated thyroid autoantibody levels have an increased likelihood of permanent hypothyroidism. 

 

In cases of neonatal hypothyroidism, the detection of anti-TPO or anti-Tg in the infant suggests transplacental antibody transfer, particularly if the mother has a history of autoimmune thyroiditis or detectable thyroid autoantibodies. Neonatal hypothyroidism is likely to be transient in these cases.

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86800

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TGAB Thyroglobulin Antibody, S 56536-6

 

Result ID Test Result Name Result LOINC Value
TGAB Thyroglobulin Antibody, S 56536-6

Forms

If not ordering electronically, complete, print, and send General Test Request (T239) with the specimen.