Parathyroid hormone, fine-needle aspiration biopsy (FNAB) - needle wash

Alphabetical Test listing

Parathyroid hormone, fine-needle aspiration biopsy (FNAB) - needle wash-994

Parathyroid hormone, fine-needle aspiration biopsy (FNAB) - needle wash
Needle wash

An adjunct to cytology examination of fine-needle aspiration specimens to confirm or exclude presence of parathyroid tissue in the biopsied area.


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.

Fine needle wash
1.5 mL
1.0 mL
  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 aliquot 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).
  • 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 - 2 hours of collection and freeze within 2 - 4 hours of collection

Plain, plastic, screw-top tube


Frozen (preferred) - 30 days

Refrigerated - 4 hours

  • Gross hemolysis
  • Gross icterus
Mayo Clinic Laboratories (PTHFN): R-NX
Mo - Sa
1 - 3 days

Electrochemiluminescence Immunoassay


An interpretive report will be provided


Parathyroid hormone (PTH) values less than 100 pg/mL suggest the biopsied site does not contain PTH-secreting tissue.


PTH values greater than or equal to 100 pg/mL are suggestive of the presence PTH-secreting tissue at the site biopsied or along the needle track. This result is dependent on accurate sampling and a total needle wash volume of greater than or equal to 1.5 mL.


This test should be interpreted in the context of the clinical presentation, imaging and cytology findings.


If the results are discordant with the clinical presentation, a sampling error at the time of the biopsy should be considered.

This test cannot distinguish between benign and malignant parathyroid tissue.