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
Refrigerated: 14 days
Frozen: 35 days
Methodology
Equilibrium Dialysis, Chromatography/Mass Spectrometry
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
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
Performing Laboratory
Quest SJC
New York DOH Approval Status
Yes