Test Code THFNA / HTGFN-M 
Methodology Immunoenzymatic Assay 
Description An adjunct to cytologic examination of fine-needle aspiration specimens in athyrotic individuals treated for differentiated thyroid cancer, to confirm or exclude metastases in enlarged or ultrasonographically suspicious lymph nodes 
Specimen Patient Preparation:
Twelve hours before this test, do not take multivitamins or dietary supplements containing biotin or vitamin B7 that are commonly found in hair, skin and nail supplements and multivitamins.

Collection Container/Tube: Plain, plastic, screw-top tube

Specimen Volume: 1 to 1.5 mL

Collection Instructions:

Needle wash specimens for analysis should be collected in conjunction with cytology specimens.

Have saline available prior to start of procedure. Saline is the only acceptable solution for needle washings.

After each fine-needle aspiration biopsy (FNAB) has been collected and the material in the needle has been expelled onto a slide for cytologic analysis, attach the used FNAB needle to an empty syringe.

Withdraw between 0.10 mL and 0.25 mL of saline up through the needle until the saline starts to fill the hub of the needle or end of the syringe.

Expel this fluid back through the needle into a separate plastic screw-top tube. This is the needle washing used for analysis.

Repeat steps 2 through 4 for each needle pass of the same biopsied site and empty into the same tube, accumulating a total of 0.5 mL to 1.5 mL of fluid to send to the laboratory. (If more than 1 site is biopsied, see Note)

Inspect specimen for visible blood or tissue contamination:

If bloody, centrifuge specimen and transfer supernatant to a new plastic aliquot tube (5-mL standard tube) to send to laboratory. The supernatant, not the cellular material, is used for analysis.

If specimen is clear, centrifugation is not necessary.

Refrigerate within 1 to 2 hours of collection. Send specimen frozen (preferred) or refrigerate to Mayo Medical Laboratories for analysis.

Additional Information

If more than 1 site is biopsied, each washing material should be submitted on a separate tube and under a different order number.

A minimum of 0.5 mL is required for testing; however, the total collection volume should not exceed 1.5 mL. Sample volumes outside these parameters may be rejected.

Do not send saline control. This test has been validated to rule-out saline matrix effect. 

Analytic Time Same Day/1 Day 
Day(s) Test Set Up Monday through Friday; 6 a.m.-9 p.m., Saturday; 6:30 a.m.-1 p.m. 
CPT Code(s) 84432