Accurate measurement of serum thyroglobulin (Tg) in patients with known or suspected antithyroglobulin autoantibodies (TgAb) or heterophile antibodies (HAb)
Reflex testing of samples with previously unknown TgAb status that prove TgAb positive during immunoassay testing
Assisting in the differential diagnosis of early phase silent thyroiditis versus Graves' disease in patients without thyroid cancer (the mass spectrometry-based method would only be required if these patients have TgAb or HAb)
Specimen Sources
Blood, ArterialBlood, CapillaryBlood, Central LineBlood, Venous
Specimen Types
Blood
Container
Red Top Tube
Collection Instructions
Specimen Type: Serum Red Container/Tube: Red top (gel tubes/SST are not acceptable) Specimen Volume: 1.25 mL Specimen Minimum Volume: 0.75 mL
Specimen Volume
Transport Instructions
Specimen Stability
Refrigerated (preferred) 7 days Ambient 72 hours Frozen 416 days
Methodology
Tryptic Protein Fragmentation, purified with Immunocapture, Analysis by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) (This service is performed pursuant to an agreement with SISCAPA Assay Technologies Inc. covering US Patent 7,632,686)
Days Performed
Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT
84432
PDM
1559866
Only Orderable at Locations:
Orderable Everywhere
Results
Component Name
Base Name
Common Name
External Name
THYROGLOBULIN, MASS SPEC, SERUM
THYROGLBMS
THYROGLOBULIN, MASS SPEC, SERUM
Thyroglobulin, Mass Spec, Serum
THYROGLOBULIN, MASS SPEC, SERUM INTERPRETATION
THYRGLBMSINT
THYROGLOBULIN, MASS SPEC, SERUM INTERPRETATION
Thyroglobulin, Mass Spec, Serum Interpretation
Result Interpretation
Healthy individuals with intact, functioning thyroid: < or = 33 ng/mL The reference ranges listed below, however, are for thyroid cancer follow up of athyrotic patients and apply to unstimulated and stimulated thyroglobulin (Tg) measurements. Ranges are based on best practice guidelines and the literature, which includes Mayo Clinic studies, and represent clinical decision levels.
Decision levels for thyroid cancer patients, who are not completely athyrotic (ie, patient has some remnant normal thyroid tissue), have not been established, but are likely to be somewhat higher: remnant normal thyroid tissue contributes to serum Tg concentrations 0.2-1.0 ng/mL per gram of remnant tissue, depending on the thyroid-stimulating hormone (TSH) level.
Tg <0.2 ng/mL: Tg levels must be interpreted in the context of TSH levels, serial Tg measurements, and radioiodine ablation status. Undetectable Tg levels in athyrotic individuals on suppression therapy indicate a minimal risk (<1%-2%) of clinically detectable recurrent papillary/follicular thyroid cancer.
Tg > or = 0.2 ng/mL to 2.0 ng/mL: Tg levels must be interpreted in the context of TSH levels, serial Tg measurements, and radioiodine ablation status. Tg levels of 0.2-2.0 ng/mL in athyrotic individuals on suppressive therapy indicate a low risk of clinically detectable recurrent papillary/follicular thyroid cancer.
Tg 2.1 ng/mL to 9.9 ng/mL: Tg levels must be interpreted in the context of TSH levels, serial Tg measurements and radioiodine ablation status. Tg levels of 2.1-9.9 ng/mL in athyrotic individuals on suppression therapy indicate an increased risk of clinically detectable recurrent papillary/follicular thyroid cancer.
Tg > or = 10 ng/mL: Tg levels must be interpreted in the context of TSH levels, serial Tg measurements and radioiodine ablation status. Tg levels of 10 ng/mL or above in athyrotic individuals on suppressive therapy indicate a significant (>25%) risk of clinically detectable recurrent papillary/follicular thyroid cancer.
