Thyroglobulin
| Category | Biochemistry >> Endocrinology |
|---|---|
| Test background |
Thyroglobulin is a dimeric glycoprotein precursor to thyroxine and triiodothyronine. It is synthesised exclusively by functioning thyroid tissue and so can be used as a tumour marker in differentiated thyroid cancer. Thyroglobulin concentration can be used as an index of tumour burden and to assess the presence or absence of functioning thyroid tissue. Note that the presence of endogenous antibodies to thyroglobulin may interfere in its measurement and so anti-thyroglobulin antibodies are therefore measured on each thyroglobulin sample. |
| Clinical Indications |
Monitoring of cancer patients post thyroidectomy. |
| Reference range | <1.0 ug/L in thyroidectomised patients |
| Sample & container required | SST (gold top), serum (red top) or heparin (green top) |
| Sample volume | 0.5 mL |
| Transport storage | Stable at 2-8°C for 24 hours. Please freeze pending dispatch for analysis. Send to lab frozen. |
| Turnaround time | 1 week |
| Notes | Grossly haemolysed samples are unsuitable for this assay. Siemens Healthcare Diagnostics has confirmed through internal investigation that the IMMULITE® 2000 XPi TG assay is susceptible to biotin interference. This occurs when biotin present in patient samples interferes (interference > 10% at concentrations > 5 ng/mL or > 20 nmol/L) with the biotin-streptavidin assay architecture on the IMMULITE platform. |