Test Overview
Clinical Utility
Thyroglobulin (Tg) is a glycoprotein exclusively produced by the follicular cells of the thyroid; therefore, detection of Tg in athyrotic individuals facilitates detection of persistence, recurrence, or metastasis of thyroid carcinoma.
Most metastases of papillary thyroid cancer occur in the lymph nodes in the neck. Suspicious nodes undergo fine needle aspiration (FNA) cytological examination to determine diagnosis. However, 1 out of every 5 samples has inadequate cellularity, necessitating Tg testing in FNA-needle wash.
Method
Immunoassay (IA)
Analytical Platform
Roche
Specimen
Specimen Type
Fine-Needle Aspiration Biopsy Needle WashFluid
Containers
Collection Containers
Sterile Container
Volume
Sample Volume
1.0 mL
Collection & Handling
Collection Instructions
Refer to Fine Needle Aspirate Biopsy Collection Instructions. Provide source of fluid. Saline is the only acceptable fluid to wash the needle.
Handling Information
Centrifuge if necessary to remove blood and/or cellular material. Freeze within 8 hours of collection. Store and send frozen.
Stability
| Ambient | Refrigerated | Frozen |
|---|---|---|
| 8 hours | 8 hours | 90 days |
Performance & Interpretation
Results
-
Thyroglobulinµg/LFine-Needle Aspiration Biopsy Needle Wash ≤ 7.4
Comment
The lab has not established reference intervals for thyroglobulin on other fluid types.
Referral Location
Canada
Interface & Setup
HL7 Interface Codes
| Order Code | Result Name | Result Codes | Units |
|---|---|---|---|
| THYROG FL | Thyroglobulin, Fluid | 62129 | ug/L |
Test Version
Last Updated
2026-01-27