.Thyroglobulin Mass Spec Serum TGMS

Synonyms

Allscripts (AEHR) Order Name

Thyroglobulin Mass Spectrometry, Serum

Sunrise Clinical Manager (SCM) Order Name

Thyroglobulin, Mass Spec, Serum

Clinical Info

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 Type

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 Stability Information:

Specimen Type	Temperature	Time	Special Container
Serum Red	Refrigerated (preferred)	7 days
	Frozen	416 days
	Ambient	72 hours

Transport Instructions

Specimen Stability

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

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.

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