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 DialysisSpecimen Type
SerumSpecimen 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 daysPerforming Laboratory
Quest Diagnostics Nichols InstituteTest 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