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Test Code FT4 T4 (Thyroxine), Free, Serum or Plasma

Performing Laboratory

Huntsville Hospital Laboratory/Madison Hospital Laboratory

Methodology

Enzyme Immunoassay (EIA)

Specimen Requirements

Container/Tube:

Preferred: Lithium heparin (light green-top)

Acceptable: Serum Gel

 Draw blood, spin down and send 1 mL (pediatric:  0.2 mL) of plasma or serum.

Specimen Stability Information

 

Specimen Type

Temperature

Time

Plasma,lithium heparin / Serum

RT, spun

5 days

 

Refrigerated, spun

7 days

 

Reject Due To

 

Hemolysis

Mild:

ok

Gross:

ok

Lipemia

Mild:

ok

Gross:

ok

Icterus

Mild:

ok

Gross:

ok

 

Reference Values

 

Age

Male (ng/dL)

Female (ng/dL)

0 – 2 days

0.8 – 2.78

0.88 – 1.93

3 – 30 days

0.48 – 2.32

0.61 – 1.93

1 – 11 months

0.76 – 2.00

0.88 – 1.84

1 – 4 years

0.90 – 1.59

1.02 – 1.72

5 – 9 years

0.81 – 1.68

0.82 – 1.58

10 – 14 years

0.92 – 1.57

0.79 – 1.49

15 – 17 years

0.92 – 1.53

0.83 – 1.44

>17 years

0.80 – 1.70

0.80 – 1.70

 

Day(s) Test Set Up

Monday through Sunday

CPT Coding

84439

Secondary ID

HHA1448

LOINC Coding

Test Name LOINC Code

T4 (Thyroxine), Free, Serum or Plasma

3024-7