T4 Free, Direct Dialysis

T4 Free, Direct Dialysis

Test Code

35167
84439
CPT Code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.
35167
84439
CPT Code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.
Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection may be available in your area for purchase through Quest Mobile.

Clinical Significance

T4 Free, Direct Dialysis - For the differential diagnosis of euthyroid hyperthyroxinemia from hyperthyroidism or for the differential diagnosis of euthyroid hypothyroxinemia from hypothyroidism.

Test Resources

Test FAQ

Hypogonadism

Test FAQ

T4, Free

Algorithm

Testing Algorithm for Thyroid Dysfunction in Nonpregnant Adults

Clinical Focus

Hypogonadism and Low Testosterone in Men: Laboratory Support of Diagnosis and Management

Clinical Focus

Thyroid Dysfunction in Nonpregnant Adults

Test Details

Patient Preparation

Fasting preferred

Methodology

Equilibrium Dialysis • Chromatography/Mass Spectrometry

Assay Category

This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Reference Range(s)

Adult0.9-2.2 ng/dL
   
Prematures, 25-30 Weeks
  Birth-7 Days0.5-3.3 ng/dL
Prematures, 31-36 Weeks
  Birth-7 Days1.3-4.7 ng/dL
Cord Blood, >37 Weeks1.2-2.2 ng/dL
Birth-4 Days2.2-5.3 ng/dL
2 Months-2 Years1.2-2.5 ng/dL
3 Years-17 Years1.0-2.4 ng/dL
   
Pregnancy
  First Trimester0.9-2.0 ng/dL
  Second Trimester0.8-1.5 ng/dL
  Third Trimester0.8-1.7 ng/dL

Alternative Name(s)

Direct Free T4,Free Thyroxine,Free T4 By Equilibrium Dialysis,FT4 Direct Dialysis,Thyroxine, Free By Direct Dialysis,Free T4 Direct Dialysis

LOINC® Codes, Performing Laboratory

Service Area must be determined
Fasting preferred

Methodology

Equilibrium Dialysis • Chromatography/Mass Spectrometry

This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Reference Range(s)

Adult0.9-2.2 ng/dL
   
Prematures, 25-30 Weeks
  Birth-7 Days0.5-3.3 ng/dL
Prematures, 31-36 Weeks
  Birth-7 Days1.3-4.7 ng/dL
Cord Blood, >37 Weeks1.2-2.2 ng/dL
Birth-4 Days2.2-5.3 ng/dL
2 Months-2 Years1.2-2.5 ng/dL
3 Years-17 Years1.0-2.4 ng/dL
   
Pregnancy
  First Trimester0.9-2.0 ng/dL
  Second Trimester0.8-1.5 ng/dL
  Third Trimester0.8-1.7 ng/dL

Alternative Name(s)

Direct Free T4,Free Thyroxine,Free T4 By Equilibrium Dialysis,FT4 Direct Dialysis,Thyroxine, Free By Direct Dialysis,Free T4 Direct Dialysis
Service Area must be determined

Preferred Specimen(s)

1 mL serum

Minimum Volume

0.5 mL

Collection Instructions

Please specify the patient's age on the request form

Transport Container

Transport tube

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

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

Reject Criteria

Lipemia • Heparin plasma • EDTA plasma

Setup Schedule

Service Area must be determined
1 mL serum
0.5 mL
Please specify the patient's age on the request form
Transport tube
Refrigerated (cold packs)
Room temperature: 4 days
Refrigerated: 14 days
Frozen: 35 days
Lipemia • Heparin plasma • EDTA plasma
Service Area must be determined
Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection may be available in your area for purchase through Quest Mobile.
Test Details

Clinical Significance

Test Resources

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.

The tests listed by specialty and category are a select group of tests offered. For a complete list of Quest Diagnostics tests, please adjust the filter options chosen, or refer to our Directory of Services.

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