Laboratory Test Information Guide

Details for Thyroglobulin, Fine Needle Aspirate

Test Name: Thyroglobulin, Fine Needle Aspirate
Alternate Name(s):  
Laboratory: Core
Specimen Type: Two samples:
The first is uncontaminated Plasma-Lyte and serves as a blank.
The second is 1 mL of Plasma-Lyte that has been used to rinse the biopsy needle as described below.
Collection Information: 1) Needle rinse specimens for analysis should be collected in conjunction with cytology specimens. After each fine-needle aspiration biopsy (FNAB) has been performed and the material in the needle has been expelled onto a slide for cytologic analysis, attach the used FNAB needle to an empty syringe.
2) Put 1 mL of Plasma-Lyte in a tube. Draw up 0.10-0.25 mL of Plasma-Lyte through the needle until it starts to fill the hub of the needle or end of the syringe.
3) Expel this fluid back through the needle into a separate tube (50-mL conical tube or other screw-top tube containing NO additive). The tube should be labelled “THRYFNR-FNA in Plasmalyt sol”. This is the needle rinse fluid used for analysis.
4) Draw up more fluid from step 2 and expel into the same tube as step 3 until 1 mL of Plasma-Lyte has rinsed the needle. Send the pooled needle rinse fluid to the laboratory. If more than one site is biopsied, needle rinse fluid from different sites should be submitted in separate tubes and under different accession numbers. The site biopsied for each specimen must be clearly identified as an order comment (not a label comment).
5) Also collect at least 1 mL of Plasma-Lyte that has not been used to rinse the needle. This should be put in a 50-mL conical tube or other screw-top tube containing NO additive and the tube should be labelled “THYRBW – Plasmalyt sol”. This will be analyzed and used as a control since the assay has not been validated using Plasma-Lyte as a sample type.
6) Deliver samples to the lab as soon as possible after collection.
Test Schedule: As required
Turnaround time from when specimen
is received in testing laboratory:
4 hours
Reference Range: ≤ 1.0 µg/L
Effective Date: 2017-07-04
Revised Date: 2019-07-30
Critical Value:  
Interpretive Comments: An elevated thyroglobulin level in the fine needle aspirate may indicate the presence of metastatic differentiated thyroid cancer.
Special Processing:  
Comments: The limit of quantitation of the assay is 0.1 µg/L. If a blank result of > 0.1 µg/L were to be obtained, a technical investigation would be performed prior to reporting of result.

The purpose of the blank fluid is to confirm that the fluid being used to rinse the needle does not have a matrix effect in the assay.
Method of Analysis: Roche Electrochemiluminescence
Critical Information Required:  
Storage & Shipment:  
System Codes: 
Referred To:  

Questions? Comments? Contact Laura Gopaul