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Test Code FFT4F T4, Free, Direct Dialysis


Specimen Required


Patient Preparation:

Fasting: 8-16 hours, preferred but not required

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collections Instructions:

1. Centrifuge and aliquot 1 mL of serum into a plastic vial.

2. Send refrigerated.


Method Name

Equilibrium Dialysis, Chromatography/Mass Spectrometry

Reporting Name

T4, Free, Direct Dialysis

Specimen Type

Serum

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  35 days
  Ambient  4 days

Reject Due To

Lipemia Reject
Heparin plasma Reject
EDTA plasma Reject

Reference Values

Prematures, 25-30 weeks:

Birth-7 days: 0.5-3.3 ng/dL

 

Prematures, 31-36 weeks:

Birth-7 days: 1.3-4.7 ng/dL

 

Cord Blood, >37 weeks: 1.2-2.2 ng/dL

 

Birth-4 days: 2.2-5.3 ng/dL

2 months to 2 years: 1.2-2.5 ng/dL

3 to 17 years: 1.0-2.4 ng/dL

Adult: 0.9-2.2 ng/dL

 

Pregnancy:

First Trimester: 0.9-2.0 ng/dL

Second Trimester: 0.8-1.5 ng/dL

Third Trimester: 0.8-1.7 ng/dL

Day(s) Performed

Monday through Saturday

Report Available

4 to 8 days

Performing Laboratory

Quest Diagnostics Nichols Institute

Test Classification

This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. The assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

CPT Code Information

84439

Useful For

Differential diagnosis of euthyroid hyperthyroxinemia from hyperthyroidism or hypothyroidism