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HelpTest ID 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.
Reporting Name
T4, Free, Direct DialysisSpecimen Type
SerumSpecimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days |
| Frozen | 35 days | |
| Ambient | 4 days |
Report Available
4 to 8 daysPerforming Laboratory
Quest Diagnostics Nichols InstituteLOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| FFT4F | T4, Free, Direct Dialysis | 6892-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| Z1571 | T4, Free, Direct Dialysis | 6892-4 |
Useful For
Differential diagnosis of euthyroid hyperthyroxinemia from hyperthyroidism or hypothyroidism
Day(s) Performed
Monday through Saturday
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
Specimen Minimum Volume
0.5 mL
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
Method Name
Equilibrium Dialysis, Chromatography/Mass Spectrometry