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Test ID FRT4D T4 (Thyroxine), Free by Dialysis, Serum

Useful For

Determining thyroid status of sick, hospitalized patients

 

Used where abnormal binding proteins are known to exist

 

Possibly useful in pediatric patients

Method Name

Equilibrium Dialysis/Tandem Mass Spectrometry (MS/MS)

Reporting Name

T4 (Thyroxine), Free by Dialysis, S

Specimen Type

Serum

Specimen Required

Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 2.6 mL

Collection Instructions: Serum must be separated from gel within 4 to 6 hours of draw.

Additional Information: Include name and telephone number of contact physician.

Forms: If not ordering electronically, complete, print, and send a Neurology Test Request Form (T732) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)

Specimen Minimum Volume

1.2 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 28 days
  Frozen  21 days
  Ambient  7 days

Reference Values

0.8-2.0 ng/dL

Reference values apply to all ages.

Day(s) and Time(s) Performed

Monday, Wednesday, Thursday; 3 p.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

84439 

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FRT4D T4 (Thyroxine), Free by Dialysis, S 6892-4

 

Result ID Test Result Name Result LOINC Value
8859 T4 (Thyroxine), Free by Dialysis, S 6892-4

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.