Thyroglobulin, Serum with Reflex to IA or LC-MS/MS




Test Mnemonic

THYRORF

CPT Codes

  • 84432 - QTY (1)
  • 86800 - QTY (1)

Performing Laboratory

Cleveland Clinic Laboratories


Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
1 mLSerumSST (Gold) Centrifuge and refrigerate. 

Alternate Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
1 mLSerumNo additive (Red) Centrifuge, aliquot and refrigerate. 

Minimum Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
0.5 mL     

Stability

Environmental Condition Description
Ambient8 hours
Refrigerated7 days
Frozen30 days

Days Performed

Mon - Fri

Turnaround Time

1 - 3 days

Methodology

Name Description
Chemiluminescence Immunoassay (CLIA) 
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) 

Reference Range

Thyroglobulin Antibody, Serum
Sex Age From Age To Type Range Range Unit
       Normal< 4.0IU/mL
Thyroglobulin by LC-MS/MS, Serum
Sex Age From Age To Type Range Range Unit
 6 Months3 YearsNormal7.4 - 48.7ng/mL
 4 Years7 YearsNormal4.1 - 40.5ng/mL
 8 Years17 YearsNormal0.8 - 29.4ng/mL
 18 Years   Normal1.3 - 31.8ng/mL
Thyroglobulin, Serum
Sex Age From Age To Type Range Range Unit
       Normal1.6 - 50.0ng/mL

Special Info

In this test, Thyroglobulin Antibody is analyzed by the Access Thyroglobulin Antibody assay (Beckman). If the result is negative (<4.0 IU/mL), the Thyroglobulin tests will be performed by immunoassay using the Access Thyroglobulin assay (Beckman). If the antibody result is positive (>=4.0 IU/mL), the Thyroglobulin tests will be performed by LC-MS/MS. Results obtained from different assay method or kits cannot be used interchangeably. Patients taking a biotin dose greater than 5 mg/day should refrain from taking biotin for at least 12 hours. Clinicians should consider biotin interference as a source of error, when clinically suspicious of the laboratory result.

Clinical Info

Serum thyroglobulin levels correlate well with the volume of differentiated thyroid tissue, hence are increased in thyrotoxicosis, thyroiditis, iodine deficiency, benign thyroid adenomas, and thyroid cancer. Thus although it is unsuitable as a screening tool for differentiated thyroid cancer (DTC), it is a highly sensitive marker for the detection of residual or recurrent disease after a total thyroidectomy and successful radioiodine remnant ablation. Presence of thyroglobulin autoantibodies interfere in the assay and thyroglobulin levels are underestimated in the antibody positive patients. In the presence of anti-thyroglobulin antibodies, thyroglobulin measurement by LC-MS/MS provides accurate thyroglobulin results. The thyroglobulin test is intended for surveillance of patients with differentiated thyroid cancer who have had a thyroidectomy with or without radioactive ablation. The presence of thyroglobulin antibodies may interfere with thyroglobulin measurement by immunoassay and cause falsely-low results.