Test Details

Mnemonic

FT4DD

Ordering Code

3432350

CPT-4 Code(s)

84439

Specimen Information

Patient Preparation

Fasting prior to draw is preferred.

Collect

Serum separator tube (SST)

Specimen Preparation

Centrifuge, separate serum from cells within 1 hour of collection and send 1.0 mL serum in a screw capped plastic vial.

Alternate Specimen

Serum: Red top

Minimum Volume

0.5 mL

Transport Temperature

Refrigerated

Rejection Criteria

Lipemia; heparin plasma; EDTA plasma

Stability

Room temperature: 4 days
Refrigerated: 14 days
Frozen: 35 days

Methodology

Equilibrium Dialysis, Chromatography/Mass Spectrometry
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Reference Range

Adult: 0.9 - 2.2 ng/dL
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 - 2 years: 1.2 - 2.5 ng/dL
3 - 17 years: 1.0 - 2.4 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
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Performing Laboratory

Quest SJC
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