Biomarker Lens

Common biomarkers

  • Hemoglobin
  • Glucose
  • ALT
  • Apolipoprotein B
  • C-Reactive Protein, Cardiac
  • Ferritin
  • Alb/Creat Ratio, Urine
  • Alkaline Phosphatase
  • FSH
  • T4,Free(Direct)

Biomarkers · Chemical

Free T4 by Dialysis/Mass Spec

Thyroxine is also called T4. T4 is a hormone that your thyroid gland makes.

Thyroxine (T4) Test, MedlinePlus, National Library of Medicine

Primary unit
ng/dL
LOINC codes
6892-4
Tests that measure Free T4 by Dialysis/Mass Spec
Quest Diagnostics 2, Labcorp 1

Ranges

Each lab publishes a reference range for the population groups it tests, usually the middle 95% of results. These intervals describe that population, not an optimal or healthy target. How ranges differ

Quest Diagnostics, T4 Free, Direct Dialysis 35167

PopulationInterval
Adult0.9-2.2 ng/dL
Prematures, 25-30 WeeksNot stated
Birth-7 Days0.5-3.3 ng/dL
Prematures, 31-36 WeeksNot stated
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
PregnancyNot stated
First Trimester0.9-2.0 ng/dL
Second Trimester0.8-1.5 ng/dL
Third Trimester0.8-1.7 ng/dL

Quest Diagnostics test catalog, 35167

Tests

Check the catalog code, specimen, method and preparation for every test that measures Free T4 by Dialysis/Mass Spec. Select up to five tests to compare them side by side.

Quest Diagnostics 2 tests

Single-analyte tests

  • T4 Free, Direct Dialysis 35167

    Serum · Fasting not stated · Turnaround Set up: Mon-Thurs; Report available: 5 days

    Method and collection
    Method
    Equilibrium Dialysis • Chromatography/Mass Spectrometry
    Preparation
    Fasting preferred
    Collection
    Please specify the patient's age on the request form
    Quest Diagnostics catalog page

Panels that include this biomarker

  • T4 Free, Direct Dialysis and T4 Total 36725

    2 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Equilibrium Dialysis • Chromatography/Mass Spectrometry • Chemiluminescence (CL)
    Preparation
    Fasting preferred
    Collection
    Please specify the patient's age on the request form
    Reference notes
    T4, Free Direct Dialysis 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 Years-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 T4, Total <1 Month Not established 1-23 Months 6.0-13.2 mcg/dL 2-12 Years 5.5-12.1 mcg/dL 13-20 Years 5.5-11.1 mcg/dL >20 Years 4.8-10.4 mcg/dL Pregnancy First Trimester 6.4-15.2 mcg/dL Second Trimester 7.4-15.2 mcg/dL Third Trimester 7.7-13.8 mcg/dL All TrimestersTogether 7.0-14.7 mcg/dL
    Quest Diagnostics catalog page

Labcorp 1 test

Single-analyte tests

  • Thyroxine (T4), Free, Dialysis/Mass Spectrometry (Endocrine Sciences) 501902

    Serum · Fasting not stated · Turnaround 6 - 11 days

    Method and collection
    Method
    Direct dialysis mass spectrometry; high-pressure liquid chromatography/mass spectrometry (HPLC/MS)
    Collection
    Serum or plasma must be separated from cells within 45 minutes of venipuncture. Send serum or plasma in plastic transport tube. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested .
    Reference notes
    See table. Age | Range (ng/dL) Premature (0 to 4 wk) | 0.86−4.46 Newborn 0 to 2 wk | 0.84−4.97 2 wk to 12 m | 0.81−2.12 Children 1 to 11 y | 0.65−1.9 Pubertal children and adults | 0.8−1.7 Pregnant female first trimester (0 to 13.3 wk) | 0.65−1.4 second trimester (13.4 to 26.6 wk) | 0.5−1.3 third trimester (>26.6 wk) | 0.5−1.1
    Labcorp catalog page

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Sources

Verify these ranges and sources

We compile this page from named laboratory catalogs, guidelines and studies. Labs calculate reference intervals from the people they test, for one assay method and one population group, so an interval describes that population rather than an optimal target.

Interpret your own results with a licensed clinician, or track your lab history and health goals in Aumnivida.

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