T4 Free, Direct Dialysis

Supply #T01 - Red/Gray SST 8.5mL

Test Code: 35167

CPT Code(s): 84439

Methodology: Direct Equilibrium Dialysis Radioimmunoassay (RAI)
Laboratory Developed Test (LDT) - This was developed and its analytical performance characteristics have been deteremined by Quest Diagnostics Nichols Institute, Chantilly, VA. It has not been cleared or approved by the FSA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Clinical Significance: Free T4 by equilibrium dialysis is the most accurate measure of Free T4. Results are independent of the concentration of the T4-binding proteins, the presence of molecular variants of these proteins, or circulating autoantibodies. Free T4 is useful in distinguishing euthyroidism from thyroid disease.

Additional names: Direct Free T4; Free T4 by Equilibrium Dialysis; Free T4 Direct Dialysis; T4 Free by Direct Dialysis; Thyroxine, Free by Direct Dialysis

Collection Guide: 

Supply: T01 - Red/Gray SST 8.5mL

Preferred Specimen: Serum

Preferred Volume: 1mL

Transport Container: Serum Separator Tube (SST)

Transport Temperature: Room Temperature

Special Instructions: Please specify on the request form the patient's age.

Specimen Stability: Room Temperature: 4 Days

Reject due: Lipemia; gross hemolysis; heparin plasma; EDTA plasma; unlabeled or improperly labeled specimens and specimens other than serum

For additional supply or collection device information, please contact DLO's Customer Service at (800) 891-2917, option 2.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.