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HelpTest Code TFNAB Thyroglobulin, Tumor Marker, Fine-Needle Aspiration Biopsy Needle Wash
Reporting Name
Thyroglobulin, FNAB Needle WashPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Confirming or excluding metastases in enlarged or ultrasonographically suspicious lymph nodes from athyrotic individuals treated for differentiated thyroid cancer in conjunction with cytologic analysis
Confirming or excluding the presence of thyroid tissue in the biopsied area from athyrotic individuals treated for differentiated thyroid cancer in conjunction with cytologic analysis
This test is not useful for screening asymptomatic individuals for neoplastic disease.
Method Name
Immunoenzymatic Assay
Necessary Information
The biopsied site of each specimen must be identified as from a lymph node or non-lymph node source, and the specific biopsy site must be clearly identified in LIS or on batch sheet.
Specimen Required
Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is 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:
1. Needle wash specimens for analysis should be collected in conjunction with cytology specimens.
2. Have saline available prior to start of procedure. Saline is the only acceptable solution for needle washings.
3. 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.
4. 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.
5. Expel this fluid back through the needle into a separate plastic screw-top tube. This is the needle washing used for analysis.
6. 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 Additional Information)
7. Inspect specimen for visible blood or tissue contamination:
a. If bloody, centrifuge specimen and transfer supernatant to a new plastic aliquot tube (5-mL standard tube) prior to sending to laboratory. The supernatant, not the cellular material, is used for analysis.
b. If specimen is clear, centrifugation is not necessary.
Additional Information
1. If more than 1 site is biopsied, each washing material should be submitted on a separate tube and under a different order number.
2. A minimum of 0.5 mL is required for testing; however, the total collection volume should not exceed 1.5 mL. Specimen volumes outside these parameters may be rejected.
3. Do not send a saline control. This test has been validated to rule-out saline matrix effect.
Specimen Type
Fine Needle WashSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Fine Needle Wash | Frozen (preferred) | 90 days | |
| Refrigerated | 14 days | ||
| Ambient | 7 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross icterus | OK |
Reference Values
Lymph node: ≤1.0 ng/mL
This cutoff has been validated for total needle wash volumes of ≤1.5 mL of normal saline. If wash volumes are substantially larger, a lower cutoff might apply.
Non-lymph node: An interpretive report will be provided.
Interpretation
Lymph Nodes:
In athyrotic patients with a history of differentiated thyroid carcinoma, thyroglobulin (Tg) concentration greater than 1.0 ng/mL in the fine-needle aspiration biopsy (FNAB) needle wash suggests the presence of metastatic differentiated follicular cell-derived thyroid carcinoma in the biopsied area.
Tg measurements yield reliable results in most cases with nondiagnostic cytology and are approximately equal in diagnostic accuracy to cytological examinations that are deemed sufficient for diagnosis.
Non-lymph nodes:
When measuring Tg in FNAB needle washes from thyroid bed tissue after total thyroidectomy and radioactive iodine ablation to differentiate thyroid versus scar tissue, an undetectable Tg concentration is consistent with the absence of thyroid-derived tissue (including thyroid carcinoma) at the site biopsied. Detectable Tg concentration is consistent with the presence of thyroid-derived tissue, but it is not indicative of the presence of malignancy.
Measurement of Tg in FNAB needle washes from a thyroid nodule may be used to distinguish parathyroid versus follicular cell derived and C-cell derived thyroid tissue but cannot identify a malignant process in the nodule.
For all other biopsied sites, eg, lung, kidney, liver, brain, bone, and various other sites, absence of measurable Tg in FNAB needle washes is consistent with the absence of thyroid-derived tissue (including thyroid carcinoma) at the site biopsied. A detectable Tg concentration is consistent of the presence of thyroid-derived tissue, but it is not necessarily indicative of the presence of malignancy.
Day(s) Performed
Monday through Saturday
Report Available
1 to 3 daysTest Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84432
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TFNAB | Thyroglobulin, FNAB Needle Wash | 53922-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TFNA3 | Thyroglobulin, FNAB, Lymph Node | 53920-5 |
| TFNA4 | Thyroglobulin, FNAB, Non Lymph Node | 53922-1 |
| TFNA5 | Thyroglobulin, FNAB, Interpretation | 69053-7 |
| TFNA6 | Lymph Node (LN) or Non-LN Source | 31208-2 |
| TFNA7 | Site Location | 39111-0 |
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.