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HelpTest Code TFC Thyroid Function Cascade, Plasma or Serum
Methodology
Chemiluminescence Immunoassay
Reflex Testing: If TSH result is ≤0.29 mIU/L, then FT4 T4 (Thyroxine), Free, Plasma or Serum will be performed. If TSH result is ≥5.1 mIU/L, then FT4 T4 (Thyroxine), Free, Plasma or Serum and TPO Thyroperoxidase (TPO) Antibodies, Plasma or Serum will be performed.
Performing Laboratory
Munson Healthcare Laboratories
Specimen Requirements
Submit only 1 of the following specimens:
Plasma
Container/Tube: Green-top (heparin) gel tube
Specimen Volume: 1 mL of heparinized plasma
Transport Temperature: Refrigerate
Collection Instructions: Centrifuge within 24
hours to separate plasma from cells. If specimen will not be
analyzed within 24 hours, send plasma frozen in plastic vial.
Forward promptly.
Note: 1. Medicare frequency limitations exist for this test in addition to diagnosis requirements.Click on link for list of medically necessary diagnoses: http://www.munsonhealthcare.org/medical-necessity. See Advance Beneficiary Notice of Noncoverage (ABN) form in Special Instructions.
2. Indicate plasma.
3. Label specimen appropriately (plasma).
Serum
Container/Tube: Gold-top serum gel tube
Specimen Volume: 1 mL of serum
Transport Temperature: Refrigerate
Collection Instructions:Centrifuge within 24 hours
to separate serum from cells. If specimen will not be
analyzed within 24 hours, send serum frozen in plastic vial.
Forward promptly.
Note: 1. Medicare frequency limitations exist for this test in addition to diagnosis requirements. Click on link for list of medically necessary diagnoses: http://www.munsonhealthcare.org/medical-necessity. See Advance Beneficiary Notice of Noncoverage (ABN) form in Special Instructions.
2. Indicate serum.
3. Label specimen appropriately (serum).
Reference Values
0.30-5.00 µIU/mL (TSH)
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
84443 - TSH
84439 - Free T4 (if performed)
86376 - TPO Antibodies (if performed)