Parathyroid Hormone, Fine-Needle Aspiration Biopsy (FNAB)-Needle Wash
Use
The Parathyroid Hormone, Fine-Needle Aspiration Biopsy (FNAB)-Needle Wash test is useful for discriminating thyroid tissue from enlarged parathyroid glands and facilitating parathyroid localization prior to surgery. It serves as an adjunct to cytologic examination of fine-needle aspiration specimens to confirm or exclude the presence of parathyroid tissue in the biopsied area. PTH values of 100 pg/mL and above suggest the presence of PTH-secreting tissue at the site biopsied or along the needle track, aiding in the diagnosis and management of parathyroid-related conditions.
Special Instructions
The test is best used in conjunction with serum PTH analysis for enhanced interpretation. Ensure that specimen collection follows proper handling and pooling protocols, with a maximal wash volume of 1.5 mL and proper identification of biopsied sites.
Limitations
Specimens should not be collected from patients receiving therapy with high doses of biotin or vitamin B7 until at least 12 hours post-administration. The assay cannot distinguish between benign and malignant parathyroid tissue and may be affected by high-dose 'hook' effects, heterophile antibodies, or interfering substances. PTH levels from the biopsy wash must significantly exceed serum levels to indicate a true positive. Specimen integrity and proper sampling are critical to prevent false results.
New York Approved
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 88106-0
- 88106-0
- 39111-0
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
1 to 1.5 mL
Minimum Volume
0.5 mL
Container
Plain, plastic, screw-top tube
Collection Instructions
Needle wash specimens should be collected in conjunction with cytology specimens. Use saline for washings, ensuring pooling of 0.5 to 1.5 mL of fluid into a plastic aliquot tube. Centrifuge if bloody and use the supernatant. Freeze within 2 to 4 hours post-collection.
Patient Preparation
Do not take multivitamins or dietary supplements containing biotin (vitamin B7) for 12 hours before specimen collection.
Storage Instructions
Send specimen frozen.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 4 hours |
| Frozen | 30 days |