Thyroglobulin Mass Spectrometry, Serum

Casandra

Casandra Test Code MC74263Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID TGMSCPT Code 84432

Thyroglobulin Mass Spectrometry, Serum

Clinical Use

Use

The test is crucial for accurately measuring serum thyroglobulin (Tg) levels in patients with antithyroglobulin autoantibodies (TgAb) or heterophile antibodies (HAb). It aids in diagnosing early phase silent thyroiditis versus Graves disease in non-thyroid cancer patients, and serves as a reflex test for unknown TgAb statuses showing positive during immunoassay testing. Given its specific detection through LC-MS/MS, it overcomes interferences from TgAb or HAb, providing reliable results, crucial for assessing thyroid cancer recurrence risk post-thyroidectomy.

Special Instructions

For electronic non-orders, complete and send Oncology or Renal Diagnostics Test Request forms with specimens. Ensure proper serum collection to avoid false readings due to potential interfering antibodies. Testing agreement with SISCAPA Assay Technologies capturing U.S. Patent 7,632,686 is in place.

Limitations

The measurement can be affected by the presence of TgAb or HAb, especially impacting immunoassay methods. Mass spectrometry offers a reliable alternative but assessing test results requires cautious comparison, especially with differing TSH levels. Variations in amino acid sequences within Tg may lead to a false-low result, impacting a small fraction of measurements. Elevated results in patients without thyroid cancer may be due to non-cancerous thyroid conditions like goiter or Graves disease, especially when including substantial thyroid remnants.

Test Details

New York Approved