Thyroxine, Free Direct Dialysis

Overview

  • EPIC Code:
  • LAB2518
  • Soft Test Code:
  • T4FR
  • Send Out Test Code:
  • 35167
Alternate Names
  • Free T4 Direct Dialysis
  • FT4 Direct Dialysis
  • T4 Free Direct Dialysis
  • T4 Free Eq Dialysis

Specimen Collection & Preparation

Patient Preparation

Fasting patients preferred


Specimen Requirements

2.0 mL Serum from a Red Top Tube in a Plastic Vial


Transport And Storage

7 days Ambient
7 days Refrigerated
28 days Frozen


Collection Instructions

 


Minimum Volume

0.2 mL Serum


Neonatal Volume

Clinical Interpretation

Reference Range:

Pregnancy Reference Ranges
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 to 7 days: 0.5 - 3.3 ng/dL
Prematures, 31-36 weeks, Birth to 7 days: 1.3 - 4.7 ng/dL
Cord Blood, > 37 weeks: 1.2-2.2 ng/dL
Birth to 4 days: 2.2 - 5.3 ng/dL
5 days to 13 days: Reference Range not established
2 weeks to 2 years: 0.8 - 2.0 ng/dL
3 years to 20 years: 1.0-2.4 ng/dL
21 years to 87 years: 0.8 - 2.7 ng/dL
> 87 years: Reference Range not established 


Test Comments:

This assay utilizes biotin technology. Patients taking vitamin supplements containing high doses of biotin (>5 mg/day) may have falsely increased test results generated.


Methodology:
  • Radioimmunoassay Direct Equilibrium Dialysis

Production Schedule

Sites Performed
  • Quest - Chantilly
Days Performed
Monday
Tuesday
Wednesday
Thursday
Departments
  • Sendouts - Clinical
Turn Around Time

4 to 7 days


Coding & Compliance

CDM

01429880


CPT Coding

84439


Medical Necessity May Apply