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Test Code PTHFN Parathyroid Hormone, Fine-Needle Aspiration Biopsy (FNAB)-Needle Wash

Reporting Name

PTH, FNAB, Needle Wash

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Discriminating thyroid tissue from enlarged parathyroid glands

 

Facilitating parathyroid localization prior to surgery

 

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

Method Name

Electrochemiluminescence Immunoassay


Shipping Instructions


Send specimen frozen.



Necessary Information


The biopsied site of each specimen must be clearly identified in the Laboratory Information System and/or 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. Draw 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)

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) to send to laboratory. The supernatant, not the cellular material, is used for analysis.

 b. If specimen is clear, centrifugation is not necessary.

8. Freeze within 2 to 4 hours of collection.

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. Sample volumes outside these parameters may be rejected.

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


Specimen Type

Fine Needle Wash

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Fine Needle Wash Frozen (preferred) 30 days
  Refrigerated  4 hours

Reject Due To

Gross hemolysis Reject
Gross icterus OK

Reference Values

An interpretive report will be provided.

Interpretation

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 between 0.5 and 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.

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

Test 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

83970

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PTHFN PTH, FNAB, Needle Wash 88106-0

 

Result ID Test Result Name Result LOINC Value
PTHF PTH, FNAB, Needle Wash 88106-0
SITEA Site 39111-0